Pakistani authorities say they have heightened security at all airports after a phone caller threatened to bomb the Islamabad airport.
Authorities at the international airport in Islamabad say security officials found no bombs at the boarding gates and lounges during a sweep of the building Thursday.
They say despite the ongoing search, all flights are on schedule.
Security officials began searching the airport after an unknown person called in a suicide bomb threat Thursday.
Rumors of bomb threats have circulated the capital since a suicide bomber detonated 600 kilograms of explosives at the Marriott Hotel in Islamabad last week, killing 53 people.
A little-known group calling itself Fedayeen Islam claimed responsibility for the Marriott attack, demanding Pakistan stop cooperating with the United States. It was not possible to verify the authenticity of the claim.
Denmark today confirmed that a member of its security services was among those killed in Saturday's Marriott attack.
Meanwhile, the U.S. State Department is prohibiting all U.S. government personnel in Pakistan from staying at, or visiting, major hotels in Islamabad, and in the cities of Karachi and Peshawar. They also are being warned to stay away from restaurants.
The U.S. Embassy in Islamabad also temporarily suspended visa services Thursday.
Some analysts say the bombing was likely in response to Pakistan's ongoing military operation in the northwestern tribal regions, where militants sympathetic to al-Qaida operate.
In the latest fighting, the Pakistani military says security forces, backed by helicopter gunships, killed at least 12 militants today in the Bajaur tribal region.
Some information for this report was provided by AP, AFP and Reuters.
