diff --git a/plonky2/src/fri/challenges.rs b/plonky2/src/fri/challenges.rs
index ad1cfa5c..82438383 100644
--- a/plonky2/src/fri/challenges.rs
+++ b/plonky2/src/fri/challenges.rs
@@ -1,12 +1,16 @@
 use plonky2_field::extension_field::Extendable;
 use plonky2_field::polynomial::PolynomialCoeffs;
 
-use crate::fri::proof::FriChallenges;
+use crate::fri::proof::{FriChallenges, FriChallengesTarget};
 use crate::fri::structure::{FriOpenings, FriOpeningsTarget};
 use crate::fri::FriConfig;
-use crate::hash::hash_types::RichField;
+use crate::gadgets::polynomial::PolynomialCoeffsExtTarget;
+use crate::hash::hash_types::{MerkleCapTarget, RichField};
 use crate::hash::merkle_tree::MerkleCap;
 use crate::iop::challenger::{Challenger, RecursiveChallenger};
+use crate::iop::target::Target;
+use crate::plonk::circuit_builder::CircuitBuilder;
+use crate::plonk::circuit_data::CommonCircuitData;
 use crate::plonk::config::{AlgebraicHasher, GenericConfig, Hasher};
 
 impl<F: RichField, H: Hasher<F>> Challenger<F, H> {
@@ -78,4 +82,50 @@ impl<F: RichField + Extendable<D>, H: AlgebraicHasher<F>, const D: usize>
             self.observe_extension_elements(&v.values);
         }
     }
+
+    pub fn fri_challenges<C: GenericConfig<D, F = F>>(
+        &mut self,
+        builder: &mut CircuitBuilder<F, D>,
+        commit_phase_merkle_caps: &[MerkleCapTarget],
+        final_poly: &PolynomialCoeffsExtTarget<D>,
+        pow_witness: Target,
+        inner_common_data: &CommonCircuitData<F, C, D>,
+    ) -> FriChallengesTarget<D> {
+        let num_fri_queries = inner_common_data.config.fri_config.num_query_rounds;
+        // Scaling factor to combine polynomials.
+        let fri_alpha = self.get_extension_challenge(builder);
+
+        // Recover the random betas used in the FRI reductions.
+        let fri_betas = commit_phase_merkle_caps
+            .iter()
+            .map(|cap| {
+                self.observe_cap(cap);
+                self.get_extension_challenge(builder)
+            })
+            .collect();
+
+        self.observe_extension_elements(&final_poly.0);
+
+        let pow_inputs = self
+            .get_hash(builder)
+            .elements
+            .iter()
+            .copied()
+            .chain(Some(pow_witness))
+            .collect();
+        let fri_pow_response = builder
+            .hash_n_to_hash_no_pad::<C::InnerHasher>(pow_inputs)
+            .elements[0];
+
+        let fri_query_indices = (0..num_fri_queries)
+            .map(|_| self.get_challenge(builder))
+            .collect();
+
+        FriChallengesTarget {
+            fri_alpha,
+            fri_betas,
+            fri_pow_response,
+            fri_query_indices,
+        }
+    }
 }
diff --git a/plonky2/src/fri/proof.rs b/plonky2/src/fri/proof.rs
index 1f9e6b16..44f74cba 100644
--- a/plonky2/src/fri/proof.rs
+++ b/plonky2/src/fri/proof.rs
@@ -375,3 +375,10 @@ pub struct FriChallenges<F: RichField + Extendable<D>, const D: usize> {
     // Indices at which the oracle is queried in FRI.
     pub fri_query_indices: Vec<usize>,
 }
+
+pub struct FriChallengesTarget<const D: usize> {
+    pub fri_alpha: ExtensionTarget<D>,
+    pub fri_betas: Vec<ExtensionTarget<D>>,
+    pub fri_pow_response: Target,
+    pub fri_query_indices: Vec<Target>,
+}
diff --git a/plonky2/src/plonk/get_challenges.rs b/plonky2/src/plonk/get_challenges.rs
index fb1517e4..59701a55 100644
--- a/plonky2/src/plonk/get_challenges.rs
+++ b/plonky2/src/plonk/get_challenges.rs
@@ -5,14 +5,17 @@ use plonky2_field::polynomial::PolynomialCoeffs;
 
 use crate::fri::proof::{CompressedFriProof, FriChallenges, FriProof};
 use crate::fri::verifier::{compute_evaluation, fri_combine_initial, PrecomputedReducedOpenings};
-use crate::hash::hash_types::RichField;
+use crate::gadgets::polynomial::PolynomialCoeffsExtTarget;
+use crate::hash::hash_types::{HashOutTarget, MerkleCapTarget, RichField};
 use crate::hash::merkle_tree::MerkleCap;
-use crate::iop::challenger::Challenger;
+use crate::iop::challenger::{Challenger, RecursiveChallenger};
+use crate::iop::target::Target;
+use crate::plonk::circuit_builder::CircuitBuilder;
 use crate::plonk::circuit_data::CommonCircuitData;
-use crate::plonk::config::{GenericConfig, Hasher};
+use crate::plonk::config::{AlgebraicHasher, GenericConfig, Hasher};
 use crate::plonk::proof::{
-    CompressedProof, CompressedProofWithPublicInputs, FriInferredElements, OpeningSet, Proof,
-    ProofChallenges, ProofWithPublicInputs,
+    CompressedProof, CompressedProofWithPublicInputs, FriInferredElements, OpeningSet,
+    OpeningSetTarget, Proof, ProofChallenges, ProofChallengesTarget, ProofWithPublicInputs,
 };
 use crate::util::reverse_bits;
 
@@ -219,3 +222,58 @@ impl<F: RichField + Extendable<D>, C: GenericConfig<D, F = F>, const D: usize>
         FriInferredElements(fri_inferred_elements)
     }
 }
+
+impl<F: RichField + Extendable<D>, const D: usize> CircuitBuilder<F, D> {
+    pub(crate) fn get_challenges<C: GenericConfig<D, F = F>>(
+        &mut self,
+        public_inputs_hash: HashOutTarget,
+        wires_cap: &MerkleCapTarget,
+        plonk_zs_partial_products_cap: &MerkleCapTarget,
+        quotient_polys_cap: &MerkleCapTarget,
+        openings: &OpeningSetTarget<D>,
+        commit_phase_merkle_caps: &[MerkleCapTarget],
+        final_poly: &PolynomialCoeffsExtTarget<D>,
+        pow_witness: Target,
+        inner_common_data: &CommonCircuitData<F, C, D>,
+    ) -> ProofChallengesTarget<D>
+    where
+        C::Hasher: AlgebraicHasher<F>,
+    {
+        let config = &inner_common_data.config;
+        let num_challenges = config.num_challenges;
+
+        let mut challenger = RecursiveChallenger::<F, C::Hasher, D>::new(self);
+
+        // Observe the instance.
+        let digest =
+            HashOutTarget::from_vec(self.constants(&inner_common_data.circuit_digest.elements));
+        challenger.observe_hash(&digest);
+        challenger.observe_hash(&public_inputs_hash);
+
+        challenger.observe_cap(wires_cap);
+        let plonk_betas = challenger.get_n_challenges(self, num_challenges);
+        let plonk_gammas = challenger.get_n_challenges(self, num_challenges);
+
+        challenger.observe_cap(plonk_zs_partial_products_cap);
+        let plonk_alphas = challenger.get_n_challenges(self, num_challenges);
+
+        challenger.observe_cap(quotient_polys_cap);
+        let plonk_zeta = challenger.get_extension_challenge(self);
+
+        challenger.observe_openings(&openings.to_fri_openings());
+
+        ProofChallengesTarget {
+            plonk_betas,
+            plonk_gammas,
+            plonk_alphas,
+            plonk_zeta,
+            fri_challenges: challenger.fri_challenges::<C>(
+                self,
+                commit_phase_merkle_caps,
+                final_poly,
+                pow_witness,
+                inner_common_data,
+            ),
+        }
+    }
+}
diff --git a/plonky2/src/plonk/proof.rs b/plonky2/src/plonk/proof.rs
index 2cf0a885..a9bb1210 100644
--- a/plonky2/src/plonk/proof.rs
+++ b/plonky2/src/plonk/proof.rs
@@ -3,7 +3,9 @@ use rayon::prelude::*;
 use serde::{Deserialize, Serialize};
 
 use crate::fri::oracle::PolynomialBatch;
-use crate::fri::proof::{CompressedFriProof, FriChallenges, FriProof, FriProofTarget};
+use crate::fri::proof::{
+    CompressedFriProof, FriChallenges, FriChallengesTarget, FriProof, FriProofTarget,
+};
 use crate::fri::structure::{
     FriOpeningBatch, FriOpeningBatchTarget, FriOpenings, FriOpeningsTarget,
 };
@@ -242,6 +244,14 @@ pub(crate) struct ProofChallenges<F: RichField + Extendable<D>, const D: usize>
     pub fri_challenges: FriChallenges<F, D>,
 }
 
+pub(crate) struct ProofChallengesTarget<const D: usize> {
+    pub plonk_betas: Vec<Target>,
+    pub plonk_gammas: Vec<Target>,
+    pub plonk_alphas: Vec<Target>,
+    pub plonk_zeta: ExtensionTarget<D>,
+    pub fri_challenges: FriChallengesTarget<D>,
+}
+
 /// Coset elements that can be inferred in the FRI reduction steps.
 pub(crate) struct FriInferredElements<F: RichField + Extendable<D>, const D: usize>(
     pub Vec<F::Extension>,
diff --git a/plonky2/src/plonk/verifier.rs b/plonky2/src/plonk/verifier.rs
index 46d41bfe..da5c9718 100644
--- a/plonky2/src/plonk/verifier.rs
+++ b/plonky2/src/plonk/verifier.rs
@@ -30,9 +30,9 @@ pub(crate) fn verify_with_challenges<
     verifier_data: &VerifierOnlyCircuitData<C, D>,
     common_data: &CommonCircuitData<F, C, D>,
 ) -> Result<()> {
-    assert_eq!(
-        proof_with_pis.public_inputs.len(),
-        common_data.num_public_inputs
+    ensure!(
+        proof_with_pis.public_inputs.len() == common_data.num_public_inputs,
+        "Number of public inputs doesn't match circuit data."
     );
     let public_inputs_hash = &proof_with_pis.get_public_inputs_hash();