Libya has pledged to abandon its efforts to develop weapons of mass destruction and that entitles it to rejoin the world community, British Prime Minister Tony Blair said Friday.

The two countries had been negotiating the issue, he said in a television address.

Libya has agreed to limit its missiles to 300 kilometres, and will sign international treaties on chemical and nuclear weapons,  Blair said.

"This decision by Col. (Moammar) Gadhafi is an historic one and a courageous one, and I applaud it," he said. It showed the proliferation problem can "with good will, be tackled with discussion and engagement," he said.

In a televised statement from the White House, U.S. President George Bush said the discussions have been been ongoing for about nine months after the governments of the U.S. and Britain were contacted by a personal envoy of Gadhafi.

"He has agreed immediately and unconditionally to allow inspectors from international organizations to enter Libya," he said.

They will be looking for evidence of nuclear, biological and chemical weapons and their delivery systems such as missiles. They will also help oversee their destruction, he said.

Libya isn't believed to have nuclear weapons, although it had tried for years to develop one. There were reports that British officials say they have been shown a significant quantity of chemical agents. Libya has also admitted to a research program to develop biological weapons.

Ending proliferation "is one of the highest priorities on the war against terror," Bush said.

In noting the terror attack of Sept. 11, 2001 which killed almost 3,000 people, Bush said terrorists, "if they ever gained weapons of mass destruction, would kill hundreds of thousands without hesitation ... and without mercy."

Bush said the U.S. and its allies have been fighting against weapons proliferation on many fronts, from increased intelligence activities, diplomacy -- "and to the decisive actions that are sometimes needed," which could be seen as a reference to the war in Iraq.

"All these actions by the United States and our allies have sent an unmistakable message to regimes that seek or possess weapons of mass destruction: Those weapons do not bring influence or prestige; they bring isolation and otherwise unwelcome consequences."

As Libya moves forward on dismantling its weapons programs and joining the fight against terrorism, its good faith will be rewarded, Bush said.

Libya's move is a major policy shift for the North African, oil-rich nation. For decades, Libya has been a pariah and a state sponsor of terrorism. It admitted responsibility for this spring for the Lockerbie bombing, the 1998 bombing of a Pan Am jet over Scotland which killed 270 people.

In 1986, the U.S. tried to kill Gahdafi with a bombing strike.

When the United Nations voted to lift sanctions against Libya earlier this month, the U.S. abstained and maintained its own sanctions. That was because of Libya's human-rights violations, its role in perpetuating regional conflicts in Africa and its pursuit of weapons of mass destruction, U.S. officials have said.