Iraqi politicians are holding more talks on forming a unity government as another U.S. congressional delegation visits Baghdad to check on their progress.

U.S. Senator John McCain met in Baghdad with officials who have been trying to form a government for the past three months. McCain said he is guardedly optimistic that officials can agree on a government within weeks.

Separately, U.S. Ambassador to Iraq, Zalmay Khalilzad, said the country is at a defining moment. He said Iraqi leaders are struggling to form a government and bring under control the violence that grips the nation.

In the latest violence, a roadside bomb killed four Iraqis in Baghdad Saturday. Police also found 10 more bodies that showed signs of torture in the city. North of the capital, another roadside bomb killed two Iraqis.

Some information for this report was provided by Reuters, AFP and AP.