Another American soldier has died and 16 are injured after another round of attacks against U.S. forces in Iraq. U.S. forces also killed 11 Iraqis in a counterattack after a U.S. convoy was ambushed.

The U.S. soldier who was killed was shot while guarding the Baghdad museum (search). The Pentagon identified him as Private First Class Edward J. Herrgott of Shakopee, Minn. He was 20.

The latest attacks cast a shadow over the July 4th holiday for the 150,000 U.S. troops stationed in Iraq.

The ambush took place on a highway in Balad (search), about 55 miles north of Baghdad Friday, hours after mortar rounds slammed into a U.S. base in the same area, injuring 16 American soldiers.

The U.S. military said 11 men attacked the convoy with rocket-propelled grenades and small arms fire. Soldiers of the Army's 4th Infantry Division (search) fired back, killing all the men. None of the Americans was injured in this counterattack.

The Coalition Press Information Center (search) confirmed that 16 U.S. soldiers were injured; 14 of those were treated and returned to duty while two were rushed to a military hospital and are in stable condition. Early reports from U.S. Central Command put the wounded toll at 19. The Associated Press reported that 18 were injured.

Two soldiers were seriously injured, with one undergoing surgery in a hospital located on the base and another evacuated for treatment, said Maj. Edward Bryja, of the Army's 3rd Corps Support Command. Others suffered cuts and small punctures from flying shrapnel, and nine soldiers quickly went back to duty, Army officials said.

Soldiers said flares and tracer bullets sliced across the night sky after the blasts.

"This is the first time the base was attacked -- and the first time we've seen mortars," said Sgt. Grant Calease, who said he and other soldiers would nonetheless carry on with a July 4th steak barbecue.

The wounded soldiers belonged to Task Force Iron Horse, a 33,000-member unit that has been staging raids in the mainly Sunni Muslim areas. The task force includes soldiers from the Army's 3rd and 4th infantry divisions, as well as the 101st Airborne Division and 173rd Airborne Brigade.

On Friday, attackers detonated an explosive on a highway in the Kadimyah neighborhood of Baghdad's western outskirts, injuring three passengers in a civilian car and two U.S. soldiers traveling in a Humvee convoy, according to an Associated Press photographer on the scene.

CPIC confirmed that one U.S. soldier was injured in this attack. CPIC said an Iraqi truck pulled in front of the convoy and an explosion occurred. The wounded soldier suffered shrapnel wounds. The exact cause of the blast is being investigated.

On Thursday evening, a sniper shot and killed a U.S. soldier manning the gunner's hatch of a Bradley fighting vehicle outside the national museum. The soldier was taken to a military hospital, but died of his wounds, Pruden said. His name was not immediately available.

Hours before the attack, the national museum displayed several artifacts that were looted after the fall of Baghdad and later recovered. The museum also showed several items from the Treasures of Nimrud, which were found hidden in a bank vault weeks ago. Curators acknowledged that many of the museum's treasures remain unaccounted for.

U.S. soldiers have been beset by daily attacks from an increasingly bold insurgency, raising fear of a political and military quagmire just two months after President Bush declared an end to major combat on May 1.

U.S. forces have come under an average of 13 daily attacks over the past six weeks. Hostile fire has killed at least 27 American soldiers in Iraq since major combat was declared over and six British soldiers have died in that same period.

Despite the attacks, many of the U.S. troops planned July 4th barbecues at bases around the country.

"We should be celebrating with our families. It is sad. Everybody wants to go home. I am glad that we came here to liberate Iraq, but I think it is time for soldiers to see their families," said Sgt. Thas Eagans from Irving, Texas.

A few were invited to join Arnold Schwarzenegger for a screening at Baghdad International Airport of the muscle-bound actor's latest movie, "Terminator 3: Rise of the Machines."

Schwarzenegger addressed a rambunctious crowd of soldiers in one of Saddam Hussein's former presidential palaces located inside the airport compound.

"It is really wild driving around here, I mean the poverty, and you see there is no money, it is disastrous financially and there is the leadership vacuum, pretty much like in California right now," he said.

Schwarzenegger, 55, has indicated he may run for governor of Californian as a Republican if residents there vote to recall the Gov. Gray Davis.

"I play terminator, but you guys are the true terminators," he told the soldiers, before heading to the base at Balad that came under attack.

In the north, American forces planned joint celebrations with Kurdish officials. The Kurds celebrate July 4 as the anniversary of their first government's election in 1992.

U.S. officials have said the insurgency is being fueled by doubts about Saddam's fate and crushing it is crucial.

The American sweep, dubbed Sidewinder, has netted at least 20 "high-value" targets, but none of the most wanted Iraqi fugitives. Arms and ammunition, including hundreds of rocket propelled grenades, or RPGs, have also been seized.

On Thursday, U.S. troops near Baqouba, northeast of the capital, tried to lure attackers into an ambush on a stretch of road known as "RPG Alley" because of the frequent attacks on U.S. forces there. One suspect was killed and three captured in the operation, said Lt. Kurt Chapman, with the Army's 4th Infantry Division.

Also Thursday, Washington put a $25 million bounty on Saddam Hussein's head and offered $15 million for information leading to the capture of either of his sons, Udai and Qusai.

The last reported sighting of Saddam was on April 9, a day before the capital fell, in northeast Baghdad. He was the target of at least two major U.S. air strikes, but there was never any proof either was successful. Based on information from captured colleagues, officials believe they were not.

The Associated Press contributed to this report.