Ending the series of unsuccessful ceasefires, the United Nations Protection Force (UNPROFOR) was deployed to Croatia to supervise and maintain the agreement. A stalemate developed as the conflict evolved into static trench warfare, and the JNA soon retreated from Croatia into Bosnia and Herzegovina, where a new conflict was anticipated. Serbia continued to support the RSK, but a series of HV advances restored small areas to Croatian control as the siege of Dubrovnik ended, and Operation Maslenica resulted in minor tactical gains.