Pakistani High Commissioner Bashir Wali Mohammed was leaving a ceremony marking Pakistan's Independence Day, which fell on Monday, when a "timed device" exploded as his convoy passed, Foreign Ministry spokesman Tasnim Aslam said.
Mohammed was not hurt in the blast, which slightly damaged his car and critically wounded three of his Sri Lankan bodyguards, Aslam said.
"The high commissioner was targeted in this attack," Aslam told The Associated Press. "He was coming back from the Pakistani High Commission to his residence after a flag-hoisting ceremony to mark Independence Day when a timed device went off in a three-wheeler rickshaw."
"We strongly condemn the attack and regret the loss of the seven lives," Aslam said.
Aslam spoke by telephone with Mohammed and she said the diplomat "sounded calm but obviously was upset with the attack and casualties sustained."
Aslam said the attack was the first to target a Pakistani diplomat in Sri Lanka.