BAGHDAD, Iraq (AP) _ A pickup truck loaded with explosives blew up today near two buses, one of them carrying members of an Iranian exile opposition group, killing seven and injuring 37, a spokesman for the group said.

The morning explosion occurred near a hospital in a northern suburb of Baghdad, the Iraqi capital, Farid Soleimani of the Iraq-based Mujahedeen Khalq group told The Assiated Press.

He said the group holds the ``clerical regime of Iran's Intelligence Ministry'' responsible for the attack.

Among the dead were six senior members of the group, including Fariba Mouzarmi, a candidate for membership in the Mujahedeen's leadership council, Soleimani said. Some of the 21 injured Iranians were in serious condition, he said.

The explosion also killed an Iraqi and injured 16 others traveling in a separate bus that was passing by at the time of the explosion, Soleimani said.

A statement issued by Massoud Rajavi, the group's leader, said the opposition has a right to respond and defend itself against the ``religious, terrorist dictatorship ruling Iran.''

On Saturday, two bomb blasts apparently intended to damage the Mujahedeen headquarters in Baghdad instead slightly injured a teen-ager and damaged other buildings and cars.

The Mujahedeen Khalq, which has a close relationship with the Iraqi government, has more than 30,000 militarily trained men and women in 17 camps near the Iranian border. The group's fighters often target Iranian government sites.

Iran also hosts Iraqi opposition groups, and Baghdad accuses Tehran of using the groups to foment trouble in Iraq. The exiled dissidents have been blamed for assassination attempts on several Iraqi leaders, including President Saddam Hussein's son, Odai.