Foreign Secretary Jack Straw (search) said Thursday that five Britons jailed at the U.S. military prison in Guantanamo Bay (search), Cuba, will be returned home in several weeks. But they could be arrested again upon arrival.

Straw told reporters at a news conference that discussion were continuing on the fate of the remaining four British citizens being held.

"Once the detainees are back in the U.K., I understand that the police will consider whether to arrest them under theTerrorism Act 2000 (search) for questioning in connection with possible terrorist activity," he said.

Earlier Thursday, Danish Prime Minister Anders Fogh Rasmussen told his parliament that a Dane held at Guantanamo Bay will soon be released.

Danish media have identified him as Slimane Hadj Abderrahmane. He was transferred to the U.S. Naval base in Cuba in February 2001 after being captured in Afghanistan.

"Under Danish law it is not possible to put him on trial. He will come to Denmark as a free man," Foreign Minister Per Stig Moeller said during a debate in parliament.

State Department spokesman Richard Boucher said the detainee would be released soon. He did not provide a more specific time frame.

He said Secretary of State Colin Powell had spoken with the Danish Foreign Minister Per Stig Moeller about the situation.

At the White House, spokesman Scott McClellan said the United States has received assurances from Denmark and Britain that the detainees being released will not pose "any future threat to America or our friends and allies."

Five other Guantanamo prisoners -- a Spaniard and four Saudi Arabians -- were recently released and returned to their countries for detention or prosecution.

"These detainees who are at Guantanamo Bay are people who are a threat to our country. That's why they were detained there, they are a danger to America and our friends and allies," McClellan told reporters.

"We have been provided assurances from those countries that we are returning those detainees to that they will make sure that they do not pose any future threat to America or our friends and allies," he said.

In Britain, Peter Clarke, the Metropolitan Police national coordinator for terrorism, said the returning men would face investigation.

"We have a responsibility to all communities to investigate suspected terrorist activity, which includes all the circumstances which led to the men's detention," he said.

Clarke said the probes would be held in accordance with British law.

Britain has been pressing for months for assurances that the nine Britons would either face trials that comply with international standards, or be repatriated.

Regarding the Britons who will remain in Cuba, Straw said: "There are a range of security and other issues which we and the Americans need to consider in respect of these four men."

He added that Britain's attorney general believed that "the military commissions, as presently constituted, would not provide the type of process which we would afford British nationals."

Moazzam Begg and Feroz Abbasi, who were listed among the first detainees likely to face trial, were among the four who will not be returned immediately, Straw said. The other two were identified as Richard Belmar and Martin Mubanga.

In Britain, the reaction to Straw's announcement was mixed.

"It's bittersweet," said Gareth Peirce, a lawyer who represents several of the detainees' families. "For the Rasul and Iqbal families there's undoubtedly a sense of relief, but for other families probably the reverse."

Negotiations about the British detainees have ground along for months. Prime Minister Tony Blair had said in October that he expected the issue to be settled within weeks. Asked about the delay, Straw said: "It was an entirely unique situation."

He said authorities had obtained useful information from the British detainees. "Valuable intelligence has indeed been obtained and it has helped to make the world a safer place," Straw said.

The five to return were identified as Rhuhel Ahmed, Tarek Dergoul, Jamal al-Harith, Asif Iqbal and Shafiq Rasul.

The Britons are among about 650 alleged Al Qaeda and Taliban fighters currently held at Guantanamo who were captured in Afghanistan and elsewhere after the Sept. 11 terror attacks.

The United States says the prisoners are "enemy combatants," not prisoners of war, and can be tried by military tribunals. But human rights groups insist their detention is unlawful.