The foreign secretary, David Miliband, said in a statement that Saudi national Shaker Aamer would not be released because the US government had "expressed significant additional security concerns" and had rejected the foreign office's request.

News of the refusal contradicted reports last Thursday that Aamer would be one of four British residents who would be released imminently from the camp, albeit to his home country of Saudi Arabia.

The continued detention of Aamer will be an embarrassment for Gordon Brown, as the release of all four men was seen as a triumph for the government, following apparently frank discussions with the US.

"They have so far declined the request for the release and return of Mr Aamer and we are no longer in active discussions regarding his transfer to the UK," said Miliband.

He said that another British resident, Ethiopian-born Binyam Mohamed, would not be released, confirming last Thursday's reports, but said the foreign office was "still discussing" his case, even though "the US government is not inclined to agree to his release and return".

Miliband confirmed that the US had agreed the release of Jordanian Jamil el-Banna, Libyan-born Omar Deghayes and Algerian Abdennour Sameur.

He said the five detainees who were the subject of the statement were the only individuals remaining at Guantánamo who had been "given leave to enter or remain in the UK under the immigration acts".

He added that the foreign office had been in contact with the families of el-Banna, Deghayes and Sameur but said the decision did not "constitute a commitment that they may remain permanently in the UK", amid concerns raised by the opposition over the threat they might pose to national security.

"We will continue to discuss with the US government how best we can work with them to see the closure of the Guantánamo Bay detention facility," he said.

The foreign secretary said he would also encourage Britain's allies "to consider taking steps similar to our own to reduce the numbers of those detained at Guantánamo Bay, such as accepting the transfer of eligible detainees, thereby hastening the closure of the detention facility".