Bombers Set Off Explosions in Pakistan. (Hat tip: Michael S.)

KARACHI, Pakistan - A series of explosions shook 18 Shell gas stations in the southern Pakistani city of Karachi early Thursday, slightly injuring four employees, police and company officials said.

Police spokesman Malik Sheikh said two men on a motorcycle went from one station to the next before dawn, placing small explosive devices in garbage cans.

“They were are all Shell pumps that were targeted,” Police Chief Kamal Shah said, adding that additional security had been deployed to several foreign-based businesses.

No one claimed responsibility for the attacks, but law enforcement officials who have raided militant organizations have seized maps of Karachi with Shell stations marked as possible targets.