LAHORE, Pakistan - A bomb blast ripped through a police checkpoint in the eastern Pakistani city of Lahore on Monday, killing seven people and wounding 18, a rescue official said.Jam Sajjad Hussain, spokesman of a state-run rescue service, told Reuters that his officials had taken seven dead bodies to hospitals."Our rescuers are at work," he said. "They have shifted so far seven bodies."Deputy Inspector General of police Haider Ashraf said the bomb exploded when the police were changing guards at the checkpoint just outside an annual religious congregation, where nearly 80,000 people were in attendance."I can at the moment say that police was the target," he said.No claim of responsibility was immediately made.