Insurgents in Iraq have stepped up attacks on civilians, soldiers and government officials, as U.S. and Iraqi forces prepare for an expected military offensive to crush the militants before January's general election.

U.S. Marines and Iraqi Security Forces have been conducting joint operations in and around the insurgent strongholds of Fallujah and Ramadi, where militants and foreign terrorists, including Abu Musab al-Zarqawi, have been operating.

The U.S. military says its warplanes successfully bombed the southeastern part of Fallujah Wednesday, hitting several munitions sites.

Meanwhile, in Baghdad, insurgents killed a senior official from Iraq's oil ministry and attacked a checkpoint near the airport with a car bomb, causing some civilian casualties.

South of the capital, an American soldier was killed and another wounded in a bomb attack.

Some information for this report provided by AFP and AP.