The American ambassador to Iraq has warned that Washington will not accept sectarianism or militias in a new Iraqi government or its security forces.

Addressing a news conference in Baghdad Monday, Zalmay Khalilzad urged Iraq's political leaders to work toward a unity government.

But he also warned that top officials in the ministries of interior, defense and intelligence, as well as the national security advisor, must be non-sectarian and must work for all Iraqis.

The U.S. ambassador says Americans will not invest billions of dollars to build Iraqi institutions if they are run by "sectarian" people.

Iraq's new parliament is due to hold its first meeting Saturday. But major political factions remain deadlocked in efforts to form a unity government.

In incidents of violence today, a suicide bombing in Mosul killed five people, and dozens of laborers were wounded in a bomb blast in central Baghdad.

In Basra, a British military officer says two Macedonian contractors kidnapped in southern Iraq last week have been released.

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