NATO said on Thursday that the alliance was making progress in Libya, but still has trouble hitting Libyan leader Muammar Gaddafi's troops.

"The difficulties are there, but we are systematically degrading Gaddafi forces," Italian Admiral Giampaolo Di Paola, president of NATO's Military Committee, said during a press conference at NATO headquarters.

Di Paola said that NATO had difficulties in bombing Gaddafi's forces, which are still playing their tactics of "shoot and scoot" after withdrawing to the outskirts of Misrata, a rebel-held city near Tripoli.

The general refused to predict how long the NATO mission in Libya would last.

"What I can say, 28 nations of the alliance have said they will continue until preconditions for Gaddafi are met. So, it is up to Gaddafi to decide when it is to stop or not," he said.