Syrian security forces have killed six civilians in separate raids as U.S. President Barack Obama and Turkish Prime Minister Recep Tayyip Erdogan met to discuss the need to “increase pressure” on President Bashar al-Assad to stop his bloody crackdown.

Tuesday's deaths occurred as heavily armed government troops searched houses near the capital, Damascus, and in central Homs province – both centers of the uprising against Mr. Assad. Rights groups and Syrian state media also reported that armed men shot dead two policemen.

The White House said Mr. Obama and Mr. Erdogan agreed at their meeting to consult on possible new steps that “could include sanctions, political pressure and other measures” against Syria. The two men held talks on the sidelines of the U.N. General Assembly in New York.

France and the United States also are pushing for the U.N. Security Council to address Mr. Assad's deadly crackdown on dissent. French Foreign Minister Alain Juppe said Monday the Security Council's silence is “unconscionable,” noting that crimes against humanity are being committed in Syria.

U.S. officials say Secretary of State Hillary Clinton told her Russian counterpart Sergei Lavrov that the Council should speak out, calling the violence in Syria inexcusable.

The U.N. human rights office says at least 2,700 people have been killed during Syria's crackdown, including 100 children.