diff --git a/src/rmp/include/rmp/blif.h b/src/rmp/include/rmp/blif.h
index c33414e4262..14ceadec716 100644
--- a/src/rmp/include/rmp/blif.h
+++ b/src/rmp/include/rmp/blif.h
@@ -38,6 +38,7 @@
 #include <stdio.h>
 #include <unistd.h>
 
+#include <atomic>
 #include <map>
 #include <set>
 #include <string>
@@ -90,7 +91,7 @@ class Blif
   std::string const1_cell_port_;
   std::map<std::string, std::pair<float, float>> requireds_;
   std::map<std::string, std::pair<float, float>> arrivals_;
-  static int call_id_;
+  static std::atomic<int> call_id_;
 };
 
 }  // namespace rmp
diff --git a/src/rmp/src/blif.cpp b/src/rmp/src/blif.cpp
index daa50438923..726f66181b3 100644
--- a/src/rmp/src/blif.cpp
+++ b/src/rmp/src/blif.cpp
@@ -62,7 +62,7 @@ using utl::RMP;
 
 namespace rmp {
 
-int Blif::call_id_ = 0;
+std::atomic<int> Blif::call_id_ = 0;
 
 Blif::Blif(Logger* logger,
            sta::dbSta* sta,