diff --git a/crates/blockifier/src/abi/constants.rs b/crates/blockifier/src/abi/constants.rs
index 563a3f3f76..b444165259 100644
--- a/crates/blockifier/src/abi/constants.rs
+++ b/crates/blockifier/src/abi/constants.rs
@@ -29,8 +29,6 @@ pub const CONSUMED_MSG_TO_L2_ENCODED_DATA_SIZE: usize =
     (L1_TO_L2_MSG_HEADER_SIZE + 1) - CONSUMED_MSG_TO_L2_N_TOPICS;
 
 // Transaction resource names.
-pub const MAX_VALIDATE_STEPS_PER_TX: usize = 1_000_000;
-pub const MAX_STEPS_PER_TX: usize = 4_000_000;
 pub const L1_GAS_USAGE: &str = "l1_gas_usage";
 pub const BLOB_GAS_USAGE: &str = "l1_blob_gas_usage";
 pub const N_STEPS_RESOURCE: &str = "n_steps";
diff --git a/crates/blockifier/src/execution/entry_point.rs b/crates/blockifier/src/execution/entry_point.rs
index 3b7a9c3bb3..bda9297017 100644
--- a/crates/blockifier/src/execution/entry_point.rs
+++ b/crates/blockifier/src/execution/entry_point.rs
@@ -202,20 +202,14 @@ impl EntryPointExecutionContext {
         let block_upper_bound = match mode {
             // TODO(Ori, 1/2/2024): Write an indicative expect message explaining why the conversion
             // works.
-            ExecutionMode::Validate => min(
-                versioned_constants
-                    .validate_max_n_steps
-                    .try_into()
-                    .expect("Failed to convert u32 to usize."),
-                constants::MAX_VALIDATE_STEPS_PER_TX,
-            ),
-            ExecutionMode::Execute => min(
-                versioned_constants
-                    .invoke_tx_max_n_steps
-                    .try_into()
-                    .expect("Failed to convert u32 to usize."),
-                constants::MAX_STEPS_PER_TX,
-            ),
+            ExecutionMode::Validate => versioned_constants
+                .validate_max_n_steps
+                .try_into()
+                .expect("Failed to convert validate_max_n_steps (u32) to usize."),
+            ExecutionMode::Execute => versioned_constants
+                .invoke_tx_max_n_steps
+                .try_into()
+                .expect("Failed to convert invoke_tx_max_n_steps (u32) to usize."),
         };
 
         if !limit_steps_by_resources || !tx_info.enforce_fee()? {
diff --git a/crates/native_blockifier/src/errors.rs b/crates/native_blockifier/src/errors.rs
index d11a11b3cd..79383d478f 100644
--- a/crates/native_blockifier/src/errors.rs
+++ b/crates/native_blockifier/src/errors.rs
@@ -72,6 +72,10 @@ native_blockifier_errors!(
 
 #[derive(Debug, Error)]
 pub enum NativeBlockifierInputError {
+    #[error("Max steps per tx out of range: {0}")]
+    MaxStepsPerTxOutOfRange(u32),
+    #[error("Max validate steps per tx out of range: {0}")]
+    MaxValidateStepsPerTxOutOfRange(u32),
     #[error(transparent)]
     InvalidNativeBlockifierInputError(#[from] InvalidNativeBlockifierInputError),
     #[error(transparent)]
diff --git a/crates/native_blockifier/src/py_block_executor.rs b/crates/native_blockifier/src/py_block_executor.rs
index fb655df210..a696d8f8d8 100644
--- a/crates/native_blockifier/src/py_block_executor.rs
+++ b/crates/native_blockifier/src/py_block_executor.rs
@@ -30,6 +30,9 @@ use crate::transaction_executor::{RawTransactionExecutionInfo, TransactionExecut
 #[path = "py_block_executor_test.rs"]
 mod py_block_executor_test;
 
+const MAX_STEPS_PER_TX: u32 = 4_000_000;
+const MAX_VALIDATE_STEPS_PER_TX: u32 = 1_000_000;
+
 #[pyclass]
 pub struct PyBlockExecutor {
     pub general_config: PyGeneralConfig,
@@ -362,6 +365,17 @@ fn pre_process_block(
     let old_block_number_and_hash = old_block_number_and_hash
         .map(|(block_number, block_hash)| BlockNumberHashPair::new(block_number, block_hash.0));
 
+    // Input validation.
+    if versioned_constants.invoke_tx_max_n_steps > MAX_STEPS_PER_TX {
+        return Err(NativeBlockifierInputError::MaxStepsPerTxOutOfRange(
+            versioned_constants.invoke_tx_max_n_steps,
+        ))?;
+    } else if versioned_constants.validate_max_n_steps > MAX_VALIDATE_STEPS_PER_TX {
+        return Err(NativeBlockifierInputError::MaxValidateStepsPerTxOutOfRange(
+            versioned_constants.validate_max_n_steps,
+        ))?;
+    }
+
     let (block_info, chain_info) = into_block_context_args(general_config, block_info)?;
     let block_context = pre_process_block_blockifier(
         state,