The FBI said the explosion had been caused by a relatively make-shift bomb: a pick-up truck packed with fertiliser and fuel oil. A $2m (£1.25m) reward was offered for information leading to the arrest of those responsible for the worst terrorist incident in US history.
Announcing the reward, Attorney General Janet Reno said the authorities had "many hundreds of leads", all of which were being pursued. Asked whether the focus of the investigation was being shifted from the Middle East, she said: "We are excluding no possibilities."
Hope was fading last night for an unknown number of people buried beneath the rubble of the Alfred Murrah federal government office building.The official death toll stood at 36, including 12 children, but officials were certain the figure would rise. At least 100 people are believed to be unaccounted for. More than 400 people were treated in hospital for injuries.
Earlier an Arab-American arrested at Heathrow, London, on arrival from Chicago, was returned to the US for questioning about the bombing. According to ABC news the man's journey had commenced in Oklahoma City soon after the bombing. Italian police said the man's luggage, intercepted in Rome, contained material useful for making bombs, including: electrical tape, silicone, a hammer, tweezers and pictures of missiles. US officials described him, mysteriously, as a possible "witness" to the bombing.
But the strong implication of a Middle Eastern connection was thrown into some confusion last night when Weldon Kennedy, the FBI special agent in charge of the inquiry, said the authorities had identified the pick- up truck used in the bombing. "Further investigation has determined that two white males were associated with this vehicle," he told a news conference. It emerged later that the two men had rented the truck in Junction City, Kansas, 250 miles north of Oklahoma City.
"These men are armed and extremely dangerous," Mr Kennedy said, issuing composite sketches. He declined to say whether they had any connection to the Middle East. Asked what an alternative motive might have been, he said: "Maybe someone out there has a grudge against the federal government." Another theory being explored was some form of drugs connection: the building included local offices of the Drug Enforcement Agency.
As the full scale of the tragedy sank in, Oklahoma's mood turned from sorrow to anger. The state's governor, Frank Keating, told reporters that he had stopped a firefighter to thank him for all he was doing. The firefighter had replied: "You find out whoever did this. All I've found in here are a baby's finger and an American flag."
As rescuers continued to pick their way painstakingly through the debris, structural engineers were drafted in to pinpoint pockets in the rubble in which survivors could still be sheltering.
President Clinton publicly urged Americans not to "jump to conclusions" that Arab elements were involved. Three Arab-American organisations had already condemned what happened, he said at a White House news conference. As reports grew of threats against Arabs and Arab-Americans, he appealed to the public not to yield to stereotypes. "This is not a question of country of origin or religion. This was murder, this was evil, this was wrong." But he left open the possibility of US retaliatory action - along the lines of the 1986 bombing of Libya - if any foreign government was proved to have been involved. Mr Clinton said this was "an attack on the US, our way of life and everything we believe in".
The other suspect - named by the Italians as Ahbram Abdallah Ammad, a US citizen of Jordanian origin - was detained when he arrived at Heathrow from Chicago yesterday morning.
Mr Clinton spoke to John Major last night and thanked him for Britain's help.Reuse content