United Nations officials say an American U.N. worker who was kidnapped two months ago in southern Pakistan has been released. Earlier in Islamabad Saturday, a suicide bomber attacked the barracks of a platoon of paramilitary forces, killing at least eight soldiers and wounding several more.

John Solecki was kidnapped during an ambush after leaving his home in the southern city Quetta on February second. He worked in the city as the head of the U.N. Refugee agency in Baluchistan province.

Gunmen killed his Pakistani driver and held him captive. Later, a previously unknown group called the Baluchistan Liberation Front demanded the government release prisoners in exchange for his freedom.

U.N. spokeswoman Jennifer Pagonis confirmed that Solecki had been released, apparently unharmed, late Saturday. "I can confirm that John Solecki has been released tonight south of Quetta. John seems tired apparently but otherwise well. U.N. staff are with him now and we're just very please that this ordeal which has gone on for two months for his family, friends and his colleagues it's now over," she said.

Earlier, a local news agency in Baluchistan said it had received a call from a man claiming to be one of his kidnappers, saying the 49-year-old aid worker had been released on humanitarian grounds.

Solecki's detention sparked an outpouring of international scrutiny.

U.N. officials repeatedly demanded his kidnappers release him because his health was in danger from a medical condition that needed regular treatment.

Meanwhile, in Islamabad, officials say a lone suicide bomber targeted the residential camp of a group of paramilitary forces charged with guarding the capital.

The attack occurred in an upscale area of the city where foreign missions and the homes of Pakistani officials are located.

Security officials said the bomber waited until dark, when the soldiers were preparing to eat dinner. He entered one of the canvas tents that serve as soldiers barracks and detonated an estimated eight kilograms of explosives. Police said soldiers fired their weapons into the air following the blast, but they say it appears there were no other attackers.

Interior Secretary Kamal Shah said officials had received intelligence about a general threat against the capital city region. He said they had no specific information about an attack on that area, but we have had information about attacks on the twin cities of Islamabad and Rawalpindi.

The bombing is latest in a wave of attacks against security forces in recent weeks. A suicide bomber struck a police station in Islamabad late last month. Last Monday, a group of militants stormed a police academy in Lahore, killing 20 recruits.

Pakistani Taliban commander and al Qaida facilitator Baitullah Mehsud has claimed responsibility for several of the plots, saying the are revenge for U.S. drone strikes against militant targets in Pakistan's tribal regions.

Early Saturday, another suspected U.S. drone fired missiles at a militant target in North Waziristan, killing 13 people.  Later a suicide car bomber struck an army checkpoint in the same region.

The escalating wave of violence has stoked fears that violence long confined to the tribal regions is now spilling into more peaceful, settled areas of the country.

Following Saturday's blast on the temporary camp of paramilitary troops in Islamabad, the chief of the Interior Ministry Rehman Malik admitted security forces are struggling to cope with the violence. "Our police forces were not prepared for such terrorist attacks and that is why the initiative of the president of Pakistan and prime minister of Pakistan is to provide more equipment - solid buildings where they should be housed. So that those who defend the people they should first be defended well," he said.

Malik said terrorists appear to be changing their method in recent weeks, abandoning the use of bomb-rigged vehicles in exchange for suicide vests. He said stopping such committed, low-profile attackers is nearly impossible.