ISLAMABAD, July 5: The British High Commission here hastily closed down its operations on Monday after it received warning from its intelligence outfit in London of a possible missile attack on the diplomatic enclave , Dawn has reliably learnt.

Informed sources told Dawn the British High Commissioner Mark Lyall received the intelligence calling for immediate evacuation of the High Commission (HC) at about 11.15am when he was in a meeting.

The warning of a possible missile attack in Islamabad was confirmed later in the evening when the US embassy also announced that its visa section would remain closed "because of a threat to the diplomatic enclave".

The 600-plus staff members of the British High Commission, including the local hires, were asked to leave immediately. They were told that due to an impending security threat the High Commission would remain closed till further notice, sources said.

"The evacuation was done on a war-footing and it was all over within 15 minutes," said one source, adding that the threat was believed to have emanated from Lashkar-e-Jhangvi.

"The High Commission has been on a high security alert for about a month now but this is the first instance that it got so serious," sources said. On being informed about the threat, members of Pakistan's security agencies also rushed to the High Commission building and combed the premises. The security cover in and around the High Commission premises has also been beefed up.

Sources in Pakistani intelligence agencies also confirmed that they had picked signals of terrorist attacks being planned on some key Western diplomatic missions in the capital. These sources said that the intelligence agencies had already launched an extensive operation to counter any terror threats.

Foreign Office Spokesman Mr. Masood Khan confirmed at his weekly briefing that the British High Commission had been shut down temporarily. Without going into details, he said: "There was a specific, credible security threat."

However, he hastened to add that there should be no cause of worry as the Pakistani authorities had taken all he necessary precautions. The alarm bells of a possible attack echoed in the diplomatic enclave throughout the day. Despite attempts by the Foreign Office to downplay it, members of the Western diplomatic community remained quite anxious.