Iraq's Foreign Minister Hoshiyar Zebari said on Monday that senior members of al-Zarqawi group were in a house in the city of Mosul when US and Iraqi forces stormed it on Saturday, causing some of those inside to blow themselves up, but it could not yet be determined whether al-Zarqawi was among those killed.
"We don't have confirmation," Zebari told Reuters during a visit to Moscow.
"In my view, I would say there must have been some key leaders of the insurgency, especially the fundamentalists - al-Qaida type of people - so I would not be surprised if he could be one of those who blew himself up," he said.
"We know that American and Iraqi forces ... surrounded a house where there was fierce resistance and when the American and Iraqi forces jointly tried to storm the building the occupants blew themselves up, they committed suicide," Zebari said.
"They believe there must have been some key leaders from the terrorists, from the fundamentalists who committed suicide instead of handing themselves up."
Zebari said only DNA tests could confirm whether al-Zarqawi was among those killed and said checks were being made.
Al-Zarqawi's al-Qaida in Iraq group has carried out many of the deadliest bombings in the country and claimed responsibility for the hotel bombings in Amman, Jordan, this month. He is known to have been active in Mosul.
Khalilzad (L) said al-Zarqawi
would be arrested or killed soon
The US military is offering a $25 million bounty for information leading to his capture or arrest.
"Unless they get a confirmation from the DNA, it will be difficult to say whether it was him or some of his lieutenants," Zebari said of the eight people killed in the gunfight and subsequent explosions.
On Sunday, a US official in Washington, speaking on condition of anonymity, said: "Efforts are under way to determine whether Zarqawi was among those killed".
But White House spokesman Trent Duffy, who was travelling with President George Bush in Asia, said it was "highly unlikely and not credible" that al-Zarqawi was among the dead in Mosul.
The US ambassador to Iraq said on Monday that al-Zarqawi's days were numbered as US forces kept up the hunt for Iraq's most wanted man following rumours he had been killed in battle.
"His days are numbered. He is going to be ultimately found," Zalmay Khalilzad said in an interview with CNN.
"Either he will be brought to justice or he will die in the battle to capture him, but we are getting closer to that goal every day. A lot of coalition forces and experts are working hard on this," he said. "It is not a question of whether but when."
"We have no indication that al-Zarqawi was killed, and we will continue operations to search for him," a US military spokesman told AFP in Baghdad.