Reform-minded ruling Uri Party lawmakers have delivered to the U.S. Embassy in Seoul a letter expressing their concerns over an American congressional bill on the North Korean human rights situation.

The bill, passed in Congress in July, is currently awaiting approval in the U.S. Senate.

The Uri legislators delivered the letter Thursday despite repeated requests to the contrary from the party leadership. The move is expected to trigger some controversy within the party.

In the letter, the South Korean lawmakers claim that U.S. moves to legislate the bill could possibly send a wrong signal to Pyongyang, hampering efforts to reduce tensions on the Korean Peninsula.