Just days after the British Museum announced that it had fired an employee who was suspected of looting its storerooms and selling items on eBay, the museum’s director announced Friday that he was resigning, effective immediately.

Harwtig Fischer, a German art historian who had led the world renowned institution since 2016, said in a news release that he was leaving the post at a time “of the utmost seriousness.”

Mr. Fischer said that it was “evident” that under his leadership the museum did not respond to warnings that a curator may be stealing items. “The responsibility for that failure must ultimately rest with the director,” Mr. Fischer said.

The museum would “come through this moment and emerge stronger,” Mr. Fischer said, “but sadly I have come to the conclusion that my presence is proving a distraction. That is the last thing I would want.”

George Osborne, the museum chair’s said in the release that the board had accepted Mr. Fischer’s decision. “I am clear about this: we are going to fix what has gone wrong,” Mr. Osborne said. “The museum has a mission that lasts across generations. We will learn, restore confidence and deserve to be admired once again.”