North Korea has denounced South Korea’s agreement with the United States on the strategic flexibility of the U.S. forces stationed in South Korea.

The North’s Foreign Ministry said in a statement Tuesday that Washington’s plan to transfer its forces in the South elsewhere in case of regional contingencies is clearly aimed at facilitating a preemptive attack against the North.

The ministry vowed to bolster the North’s military deterrent, saying that the agreement between Seoul and Washington has heightened tensions in the region

Under the pact signed last month in Washington, Seoul agreed to respect the American right to relocate its forces in South Korea to other regions in the event of contingencies. Washington, for its part, agreed not to ask Seoul to get involved in regional conflicts against its will.