U.S. regulators on Wednesday issued a second set of charges against British oil giant BP for its role in the 2010 oil spill in the Gulf of Mexico.

The U.S. Bureau of Safety and Environmental Enforcement (BSEE) accused BP of failing to conduct pressure integrity tests at the Macondo as well as failing to suspend drilling operations "when the safe drilling margin identified in the approved application for permit to drill was not maintained."

U.S. regulators in October issued an initial round of 15 violation notices to BP, Transocean and Halliburton, following a probe into the BP spill by the U.S. Coast Guard and BSEE's predecessor, the Bureau of Ocean Energy Management, Regulation and Enforcement. BP was cited for seven violations and contractors Transocean and Halliburton for four violations each.

BP has 60 days to appeal the latest citations of violations, and after that period of time, BSEE will consider what penalties should be imposed, according to U.S. media.

BP's Macondo well ruptured after the Deepwater Horizon oil rig exploded and sank in April last year, spewing up to 4.9 million barrels of oil into the Gulf for nearly three months, making it the world's worst marine oil spill.

A government report released in September blamed BP and the other companies for a series of failures that led to the spill.