NATO stepped up its airstrikes in Tripoli Monday, appearing to target Libyan leader Col. Muammar Gaddafi’s compound. The Libyan government said three people had been killed and an additional 150 were injured, but these numbers were not confirmed. At least a dozen explosions were heard Monday night, and after each blast, a NATO aircraft could be heard in the sky. The strikes came after France announced it would be joining forces with Britain to send more attack helicopters as part of the U.N. resolution to protect civilians. On Monday, U.S. Secretary of State Hillary Clinton called on more NATO countries to participate in the mission while also defending the U.S.’s role. The highest-ranking diplomat in the Middle East, Jeffrey Feltman, visited the de facto rebel capital, Benghazi, on Monday to meet with rebel forces and to show U.S. support for their campaign.