BAGHDAD, Iraq (CNN) -- Two American soldiers were killed overnight in separate attacks in Baghdad, U.S. military officials said Monday, and four others were wounded in Ramadi, west of the Iraqi capital.
A second 1st Armored Division soldier was killed around 1 a.m. Monday when an "improvised explosive device" hit his vehicle, military officials said.
There have been 30 hostile and 43 nonhostile U.S. military deaths in Iraq since President Bush declared an end to major combat operations in Iraq on May 1.
The two deaths overnight followed the point-blank killing Sunday of a U.S. soldier at Baghdad University, military officials said.
The soldier from the 352nd Civil Affairs Command had strayed from a larger group and was talking with a local resident when an assailant walked up from behind and shot him in the back of the head with a handgun, a witness told CNN. The shooting took place around 12:30 p.m. (4:30 a.m. EDT), a military spokeswoman said.
It was the second such attack in two days and the third in about a week. All three have happened in Baghdad. On Saturday, British journalist Richard Wild, 24, was fatally shot in the back of the head; another U.S. soldier was shot in the head about a week ago.
The United States has blamed remnants of Saddam Hussein's government -- Baathists and Republican Guard members -- for the attacks on coalition troops.
On Saturday, a U.S. soldier was wounded and two Humvees damaged when a grenade was tossed from an overpass at a U.S. military police patrol in central Baghdad.