The blast occurred at Sinjar, 120kms west of the main northern city of Mosul, while the troops were involved in explosive ordnance disposal (EOD), a US military spokesman said on Monday.
"There were two US soldiers killed and two wounded in northern Iraq in the Sinjar area while conducting EOD operations."
The latest US military deaths take to more than 530 the number of American soldiers killed in combat, by accident or suicide since the US-led invasion of Iraq last March.
Pipeline attack foiled
Also on Monday, US forces thwarted an attempt to blow up an oil pipeline in northern Iraq, the head of security for the country's Northern Oil Company (NOC) told AFP.
"An explosive charge of eight kilos was placed on the pipeline linking the oil fields in Kirkuk to Al-Dibis region, 50 kms north of the city," said NOC security chief Ghazi Talabani.
"The US Army Corps of Engineers defused the device, which would have been strong enough to destroy the pipeline," he added.
Since US-led forces ousted Iraqi leader Saddam Hussein 10 months ago, oil facilities in northern Iraq have repeatedly been targeted by resistance fighters resisting the US-led occupation.
The unrest continued on Monday as about 250 former Iraqi prisoners of war demonstrated outside the headquarters of the US-led occupation in Baghdad, demanding back pay and the restitution of their rights as ex-soldiers.
Former prisoners are considered
criminals by the Governing Council
The men, all residents of the ancient city of Babylon south of the Iraqi capital, carried banners in English that read "We are the captives of Iran and Saudi Arabia", and "We demand to get our rights as other captives."
The protesters - who fought in the Iraq-Iran war in the 1980s
or in the Gulf War in 1991 - said the US-appointed interim Iraqi Governing Council had refused to grant them the rights accorded to ex-soldiers upon their release.
"We tried to work when we were freed, but the (interim)
government refused. We are considered to be criminals," said Ali Mahdi Kadum, a man in his 40s.
"Most Iraqis have regained their rights (since the start of the
US-led occupation) but we have not," complained 35-year-old Hamza Mahdi Abud, who was held captive in Saudi Arabia.
Habib Abd al-Wahid Muhsin, a father of four who was imprisoned during the Gulf War, said he had not received his military pay since 1991. He sells black market cigarettes in the streets of Babylon to provide for his family.
Jafar Abd Allah Al-Juburi, a 43-year-old father of six, said he was held for 13 years with 37 other prisoners in a tent in the Saudi desert.
"I came back to Iraq four months ago, and I have nothing to help support my family," he said.