The month of May was proven the worst and most tense time of the year for Pakistan as it started with the U.S. SEALs' operation in Abbottabad city that killed al- Qaida chief Osama Bin Laden which was followed by revenging attacks by Pakistani Taliban, leaving 172 people dead and hundreds of others injured.

On one side Pakistan came under severe international criticism and embarrassment as the American high commands blamed Pakistan of "either involved" in protecting Osama or "incompetent" to know about his presence in the garrison city of Abbottabad, and on the other hand Pakistani Taliban first announced to revenge for Pakistani government and forces' role in facilitating Americans to kill Osama, and they also materialize their threats offensively.

After the Osama operation, Pakistan's main focus, to remove the bad impression about its intelligence failure, was quickly shifted to the brazen attacks on the security forces by Taliban militants to take revenge of Osama's killing despite an official confirmation from the U.S. side that cleared Pakistan's involvement.

After the death of world's most wanted man, militant attacks mostly targeted security personnel but two foreign missions also came under attack.

On May 20 Pakistani Taliban targeted U.S. consulate vehicles with a roadside car bomb blast, the first attack on Americans in Pakistan since Osama was killed, in the country's northwestern provincial capital Peshawar, killing one Pakistani civilian and wounding 11 others, including two U.S. consulate employees.

Just four days before American consulate convoy was attacked, on May 16, a Saudi diplomat was shot dead in southern coastal city Karachi by some armed motorcyclists. The incident was not clearly claimed by any group but some analysts linked it to Taliban and others take it as the result of tension between Sunni and Shia sects in the region.

The attack which shocked Pakistani government, security agencies and public came on Sunday night of May 22 when four militants of Pakistani Taliban, armed with automatic weapons, grenades and rockets, broke into the Pakistan navy air base in Karachi and killed 10 security personnel, leaving 15 others injured.

In this attack militants also succeeded in destroying Pakistani forces' premier anti-submarine attack jet, the U.S. made P-3C Orion worth 80 million U.S. dollars which was the biggest financial loss that Pakistan suffered ever in one terrorist attack.

Here are the brief details of other brazen militant attacks since Osama was killed on May 2, 2011.

On May 13: A dual suicide bomb attack killed at least 98 people and injured over 100 including majority of fresh trainees of Pakistan's frontier constabulary outside their training center in the northwestern district of Charsadda when they were returning homes after finishing their courses.

On May 18: Around 10 militants armed with rockets, mortars and automatic guns attacked a security post early morning on the outskirts of Peshawar and killed two security personnel. In the retaliation at least 20 militants were also killed during the four hours long crossfire between forces and attackers.

On May 21: At least 16 people were killed when unknown militants bombed an oil tanker in Pakistan's northwestern tribal region of Khyber Agency, bordering Afghanistan. Dozens of oil tanker and other loader vehicles, heading for Afghanistan for NATO forces, have been attacked in the area.

On May 25: Some unknown suicide bombers rammed an explosive laden vehicle into a police station in Peshawar, killing eight policemen and wounding over 30 others including some civilians. The impact of the blast was so high that it destroyed the roadside police station completely.

On May 26: In evening time a suicide bomber with his vehicle loaded with 450kg explosives, tied with detonators, targeted the police and courts offices in northwestern Hangu district killing 36 and injuring about 50 others. The attack also destroyed government offices and 15 shops completely including one restaurant where policemen used to take food. The responsibility of the attack was claimed by the Pakistani Taliban.