BAGHDAD — American Special Operations forces shot to death the son and nephew of the governor of Salahuddin Province during a raid on Sunday in the northern city of Bayji, the latest in a series of operations that have resulted in the deaths of civilians or close associates of Iraqi government officials.

The governor, Hamed al-Qaisi, threatened to resign in protest and said he would suspend cooperation with American officials.

The shootings come at a delicate time in negotiations between United States and Iraqi officials over the terms of a new security agreement. The most contentious sticking point has been an Iraqi demand that American troops no longer be immune from Iraqi criminal laws, an ultimatum that Iraqi officials say has been spurred by unwarranted attacks on civilians. A new agreement is needed for American troops to remain in Iraq after a United Nations mandate expires at the end of the year.

Iraqi Premier Steps Back on U.S. Troops Comment

BAGHDAD — On the eve of Senator Barack Obama’s visit to Iraq, its prime minister tried to step back Sunday from comments in an interview in which he appeared to support Mr. Obama’s plan for troop withdrawal.

The interview with the prime minister, Nuri Kamal al-Maliki, was published Saturday in the online version of Der Spiegel, a German magazine. It was widely picked up by American newspapers because it appeared to give an unexpected boost to Mr. Obama, the presumptive Democratic presidential nominee, who has called for an expedited withdrawal.

The interview prompted immediate concern from the Bush administration, which called to seek clarification from Mr. Maliki’s office, American officials said.