A navy official was killed as a suicide blast took place outside the Navy headquarters in the Pakistani capital of Islamabad on Wednesday, police said.

A security person guards near the blast site at Pakistan's Navy headquaters in Islamabad, capital of Pakistan, Dec. 2, 2009. The suicide bombing resulted in at least one person dead and three others injured. [Bilal Malik/Xinhua]

Deputy Inspector General of Islamabad Bin Yameen said that it was a suicide attack in sector E-8 of Islamabad at around 13:30 pm local time (0830 GMT). The attacker apparently walked up to a checkpoint at the entrance to the heavily-guarded naval complex in central Islamabad and detonated his explosives when challenged by security forces, police and witnesses said.

Islamabad Chief Commissioner Fazeel Asghar informed media on site of the blast that one unknown suicide bomber aging 17 to 18 years was standing at some distance of the main gate of the Naval Complex.

"When Naval police personnel inquired his identity and asked him for body search, the attacker removed his coat and blasted himself also killing police personnel Muhammad Ashraf," the chief commissioner said.

Police said four other people were seriously injured in the blast. The injured were shifted to PIMS hospital for treatment.

Eyewitnesses said the suicide bomber was a teenager wearing blue jacket. The blast shattered the windows of nearby buildings and vehicles.

The security forces have cordoned off the area and emergency has been imposed in Islamabad hospitals after the incident.

Security forces check a damaged car after a blast at Pakistan's Navy headquaters in Islamabad, capital of Pakistan, Dec. 2, 2009. The suicide bombing resulted in at least one dead and three others injured. [Bilal Malik/Xinhua]

Pakistani President Asif Ali Zardari and Prime Minister Syed Yousuf Raza Gilani strongly condemned the suicide attack. President Zardari said the terrorists involved in such heinous crime would not be spared and such incidents would not deter the government's resolve to fight terrorism and extremism from the country.

The violence came hours after U.S. President Barack Obama said he would send 30,000 more troops to Afghanistan, a move Pakistani officials fear will push militants across the border from Afghanistan and complicate the army's battle against the Taliban.

The attack also came a day after a Pakistani provincial lawmaker was killed in a suicide attack in northwest Swat valley, and as Taliban insurgents stepped up attacks to avenge a multi-pronged military offensive against them.

Islamabad itself was last hit in late October, when twin suicide blasts tore through the International Islamic University, killing up to five people.