Reuters is reporting that Moussa Koussa, foreign minister of Libya, has defected from Muammar Qaddafi's government. Koussa arrived in London today to seek refuge from the Libyan regime.

"He wasn't happy at all. He doesn't support the government attacks on civilians," said Koussa's friend Noman Benotman, an analyst at a British think tank. "He's seeking refuge in Britain and hopes he will be treated well."

According to BBC News, a spokesman for the Libyan government has disputed the story, saying that Koussa is "traveling abroad on a diplomatic mission."

But the British Foreign Office says that Koussa has resigned his post.

"Musa Kusa is one of the most senior figures in Qadhafi's government and his role was to represent the regime internationally – something that he is no longer willing to do," reads a statement from the Foreign Office.

Koussa had been foreign minister for two years, and had served as chief of Qaddafi's intelligence apparatus from 1994 to 2009 prior to that. The Washington Post reports that Koussa "previously had been considered likely to stick with Qaddafi to the end."

His defection comes on a day when Qaddafi's troops have made huge advances in Libya, seizing towns that rebels had claimed days earlier. It comes, too, on the same day Reuters also broke the story about Obama secretly authorizing American aid to Libyan rebels.

We're keeping an eye on the story and will update this post as more details are available.