Navy Admiral Mike Mullen, chairman of the U.S. Joint Chiefs of Staff, has warned that the civil war in Libya is moving towards stalemate, while conceding that air strikes by NATO and the U.S. have destroyed 30 percent to 40 percent of Moammar Gaddafi's ground forces.

The US government recently authorized the use of armed, unmanned Predator drones over Libya in order to make precision” attacks on the Libyan government’s military targets on the ground.

However, as exemplified by the lengthy and continuing siege in the western town of Mistrata, neither the rebel factions nor pro-Gaddafi forces have made a decisive turn towards victory.

A BBC correspondent in Tripoli wrote of the stalemate: “Neither the Libyan army nor the rebels can land knockout blows. The American decision to deploy armed, unmanned predator drones will not win the war for the rebels. But the drones give NATO another option, and at a time when the air campaign seems to be in trouble, they represent American political support as well as more American firepower.”

The Libyan government has, not surprisingly, condemned the introduction of U.S. drones into the conflict.

They [drones] will kill more civilians and this is very sad, Khaled Khaim, Libya's deputy foreign minister told the BBC. It's for the Libyans to choose their destiny - not by sending more weapons or more air strikes, or more money and weapons to the rebels. I think what they are doing is undemocratic, illegitimate. I do hope that they will reverse their decision.

In stark contrast, rebel spokesman Abdel Hafiz Ghoga told Al Jazeera: There's no doubt that [the drones] will help protect civilians and we welcome that step from the American administration.

Admiral Mullen also assured that the Libyan opposition has not been infiltrated by al-Qaeda terrorists, although he admitted Islamic radical groups could try to exploit the chaos in Libya to their advantage.

We're watchful of it, mindful of it and I just haven't seen much of it at all. In fact, I've seen no al-Qaeda representation there at all, he said.

Meanwhile, US Defense Secretary Robert Gates said there are no plans to send in American ground troops into Libya.