The United States and the United Nations closed their offices for two days in northwest Pakistan's city of Peshawar on Tuesday as a wave of fear prevailed among people with Monday bombings raising the collective death toll to 63.

As security high alert in the city, two people were shot dead including a suspected suicide bomber Tuesday by law enforcement personnel, official sources said. Suicide jackets and explosives were also recovered from the suspects.

North West Frontier Province (NWFP) is gripped with tension while people are observing three-day mourning and the security forces are on high alert.

Ten people including two Pakistani security guards and six attackers were killed in a series of suicide vehicle bomb, grenades and weapon fire at the U.S. Consulate General in the provincial capital of Peshawar on Monday.

The U.S. mission has moved the Peshawar staff to Islamabad for two days, as debris of the Monday bombing are being cleared from the U.S. mission's premises that have recently been upgraded as the Consulate General.

Announcing to close its Peshawar office and affiliated agencies ' offices for two days, the UN Tuesday postponed its all development activities in the province.

"For security reasons, United Nations' offices in Peshawar have been closed temporarily only for two days," UN National Information Officer Ishrat Rizvi told Xinhua.

"We took this step due to security threats, we have advised our staff to work from home," she added.

A four-member investigation team of U.S. experts has also arrived in Peshawar to probe the blasts outside the Consulate, a local TV reported.

Inspector General of Police Malik Naveed Khan also formed two teams to commence their probe. Investigation teams are combing the area evidences and the damage evaluation.

A statement of the U.S. Embassy in Islamabad said Monday that the Peshawar attack demonstrates desperation of the terrorists after their rejection by the people of Pakistan.

A spokesman also thanked the government of Pakistan for timely assistance to the U.S. Consulate after the terrorists attack.

Frightened People were also mourning in another place Timergarah, Lower Dir district in Northwest Pakistan, as they buried coffins of 53 persons killed Monday when a suicide bomber exploded him in a gathering of 800 political workers of the Awami National Party (ANP) .

"The ANP has become target as it has taken a firm stand against Taliban and terrorism," said an ANP worker from Lower Dir area with request of not disclosing his name.

In retaliation Pakistani security forces killed at least 10 militants and destroyed five hideouts in nearby Orakzai tribal agency in Northwest Pakistan, a local TV channel reported.

The Orakzai Agency military operation has killed more than 250 militants in the past 10 days, and has displaced more than 60,000 people from the area.