Gunmen on Sunday killed six people and kidnapped five others in separate attacks in Iraq's western province of Anbar, officials said.

Among those killed were three Syrian truck drivers, while three police were among those kidnapped.

Armed men shot dead the Syrian truck drivers and set their vehicles on fire near the town of Al-Rutba, close to the Syrian border, a local administrative official and police said.

A civilian and a policeman were kidnapped from the site where the truck drivers came under attack, while armed men abducted two more police and a civilian from north of Al-Rutba.

It was unclear if the same group of gunmen carried out all the kidnappings.

In a separate incident, an army lieutenant colonel was shot dead in the city of Fallujah, while a sniper killed a soldier east of the city, officials said.

In another attack, armed men killed a cousin of Anbar provincial chief and wounded his wife in Fallujah.

Iraq has been hit by a wave of violence that killed more than 600 people in May, raising fears of all-out sectarian conflict.

Violence has fallen from its peak in 2006 and 2007, when more than 1,000 people were killed in some months, but death tolls have started to rise again.