How to create AWS RDS Aurora Postgres Read Replica using Terraform

Hi Team,

I created a Aurora Postgres cluster and instance with terraform. I also need to create a read replica there. I tried with the following.

resource "aws_rds_cluster" "sample_db_cluster" {
  cluster_identifier = "${var.base_name}-read-replica"
  engine             = "aurora-postgresql"
  engine_mode        = "provisioned"
  engine_version     = "16.1"
  skip_final_snapshot    = true
  storage_encrypted = true
  replication_source_identifier = <arn-of-source-db-cluster>

But it gives this error always.

InvalidParameterCombination: The DB engine aurora-postgresql doesn’t support cross-region read replicas.

I also tried by adding source_region to the resource block but it does’t work.

Terraform version: ~> 4.0

What am I missing?