At least three policemen were injured in a blast that occurred early Friday morning in Peshawar, the largest city in northwest Pakistan, reported local Urdu TV channel Samaa.

Further details about the blast are not immediately available.

This is the third blast reported Friday morning in the country. Prior to this, Pakistan Taliban launched a twin suicide blast early Friday morning at an armed police training center in Charsadda, a city some 30 kilometers northeast of Peshawar. The blasts, which took place at about 6:10 a.m. local time, have so far reportedly killed at least 66 security personnel, ten civilians and injured more than 70 others.

Hospital sources said that about 20 out of the 70 injured in the twin suicide blasts were in critical condition and the death toll could further rise.

Friday morning's attack at a police training center in Charsadda is the most serious one of its kind in Pakistan since the killing of the al-Qaida chief Osama bin Laden by the U.S. special task forces in Pakistan's northwestern city of Abbottabad on May 2. Both al-Qaida and Pakistan Taliban have vowed to avenge the death of bin Laden by threatening to launch attacks in Pakistan as well as in other places of the world.

About two hours after the twin suicide blasts were reported, Pakistan Taliban (TTP) has claimed the responsibility for the attack.

Local watchers believe that more serious terrorist attacks could follow either in Pakistan or in other places of the world.