An Islamic militant group denied Sunday that it had killed Cpl. Wassef Ali Hassoun, a day after statements attributed to the group on two Web sites said that the U.S. Marine had been beheaded.

The Ansar al-Sunna Army said on its Web site that it had not issued the statements and that there was "no basis of truth" in the reports of Hassoun's death.

The group's response left unclear whether Hassoun, 24, was still alive. U.S. military officials said they were checking into the claim of Hassoun's death but had no confirmation Sunday. Nor was it possible to confirm whether either of the announcements had been made officially by Ansar al-Sunna.

Hassoun, a member of the 1st Marine Expeditionary Force, disappeared from his unit in Iraq on June 19. A week later, the Arab satellite television network al-Jazeera aired a videotape of the Lebanese-born Marine, blindfolded and with a sword held over his neck, and a message from a group calling itself Islamic Response saying that it had captured Hassoun and threatening to kill him. It was not known whether the group is connected to the Ansar al-Sunna Army.

The Lebanese Foreign Ministry initially said that its officials in Baghdad had made contact with people who had "indirect links" to the kidnappers, and that they had confirmed Hassoun's slaying. But the Foreign Ministry later said its announcement was "not official."

The confusion over Hassoun came on an American holiday that was otherwise relatively quiet in Iraq.

The 1st Armored Division, which has been in Iraq for 15 months, the longest tour of any American combat unit, began preparing to return home after an official ceremony in Baghdad.

The division, which has lost 135 soldiers and lists 1,100 wounded, has had as many as 36,000 troops in Iraq. It was scheduled to leave three months ago but its stay was extended. Military officials declined to specify the troop strength now.

"We have learned a lot about the price of freedom," the division commander, Maj. Gen. Martin Dempsey, said in an Independence Day speech. "People experiencing freedom for the first time may not understand how fragile it can be."

Meanwhile, Iraqi National Guardsmen said they foiled an attack northeast of Baghdad by shooting the driver of a bomb-laden car as he attempted to steer the vehicle into their guard station. Two bystanders were killed in the incident.

According to Iraqi police, the driver shouted "God is great" as he tried to drive through a checkpoint outside the station. Guardsmen opened fire, and the car exploded.

Also Sunday, a rebellious Shiite Muslim cleric, Moqtada Sadr, indicated that he might resume fighting U.S. troops. Battles between U.S. troops and Sadr's followers, centered in four cities south of Baghdad, have killed about 20 Americans and hundreds of Iraqis. The fighting was quieted by a tenuous truce brokered last month by Iraqi officials and clerics.

"We promise the Iraqis and the whole world in general to continue resisting the oppression and occupation until the last drop of blood," said a statement from Sadr's office in the Shiite holy city of Najaf. "There is no truce with the occupier and with those who cooperate with the occupier."

Sadr has said he would form a political party and participate in national elections scheduled for January. He also ordered his followers to cooperate with Iraqi police against foreigners staging attacks that have killed Iraqis.

A spokesman for Sadr, Ahmed Shaibani, said: "The truce is ended today. One of the conditions we put for the truce is that the government should end the occupation. The government did not end the occupation."

Elsewhere, police officials said that saboteurs had blown up part of a pipeline carrying crude oil from fields in northern Iraq, the Associated Press reported. Fire crews and police from nearby cities worked into the night to extinguish the blaze near Musayyib, about 40 miles south of Baghdad. Pipelines in that area have been hit several times in the past few weeks.

Cpl. Wassef Ali Hassoun's father, Ali Hassoun, displayed a photograph of his son last week at his home in Lebanon. U.S. officials have been unable to confirm if the Marine is alive.