Three Pakistani school children, aged between 10 and 15 years, and four foreign aid workers have been killed in a bomb attack at the inauguration of a girls' school in northwest Pakistan. Journalists are among the dozens of injured.

Authorities said more than 60 were hurt in the latest explosion near Swat Valley, an area the military had largely cleared of militants in an offensive nearly a year ago. The blast, triggered by a remote-controlled device, went off just as a convoy with local dignitaries, aid workers and journalists arrived at the school.

The school - situated in the village of Koto in the Lower Dir district - was blown up a year ago in January 2009 and rebuilt with the help of a foreign NGO. Three of the nine school rooms were completely destroyed in today's attack. The number of fatal casualties is expected to rise as the building was full of children at the time of the explosion.

Pakistan's Taliban militants have bombed markets, schools, as well as military and police facilities despite major government crackdowns that have destroyed some of the bases and US drone aircraft attacks that have killed some of their leaders. The death toll from a drone attack on Tuesday night has risen to 31.

Pakistani troops in Swat Valley during offensive in 2009. Photo Al Jazeera English (Flickr.com)