The British military estimates that operations in Libya have cost about 250 million EGP (U.S. $400 million) so far, according to media reports late Wednesday. The Defense Ministry was due to set out the costs of the operation in a written statement to Parliament, according to Sky News and the BBC. Officials declined to comment on reports, but Britain's Treasury chief George Osborne had previously promised that an accounting of the military's Libya-related expenses would be made in the coming days. On Sunday, his deputy Danny Alexander told Sky that the bill for the operation could run "potentially into the hundreds of millions as it goes on." Britain is, along with France, among the leading members of the NATO-led force which has operated over Libya since mid-March. British Tornado and Typhoon fighter jets have carried out almost daily raids on targets in Libya, and the country has also sent in Apache attack helicopters to boost the mission's firepower. But the U.K. military is under strong pressure from spending cuts and a grueling commitment in Afghanistan. Senior military officials have warned that the country may begin to show signs of strain if the mission carries on past the summer. Prime Minister David Cameron has insisted that the NATO-led alliance was "holding strong," and would complete its task in Libya. "When you look at what's happening in Libya, where you see a strengthening of the revolt in the west of Libya, you see more people deserting Gadhafi's regime," Cameron told lawmakers in the House of Commons. "You see growing unpopularity in his regime and indeed our coalition holding strong, I think time is on our side, the pressure is growing and I believe we will take it to a satisfactory conclusion." The air campaign continued Wednesday. At least two explosions shook Tripoli before noon as fighter jets soared overhead. It wasn't immediately clear what had been hit or if there were casualties.