By David Brunnstrom
BRUSSELS (Reuters) - NATO said on Tuesday it had destroyed dozens of tanks and other armored vehicles besieging the Libyan city of Misrata, but conceded there were limits to what air power could do to end the siege.
"We have been watching the situation in Misrata, and over the past 10 days fighting has been intense," Brigadier-General Mark Van Uhm, a member of NATO's military staff, said.
"Our forces have conducted numerous strikes in and around Misrata, and we have destroyed over 40 tanks and several armored fighting vehicles there," he told a news conference.
The Western military alliance's pilots also destroyed mobile rocket launchers belonging to Muammar Gaddafi's forces that were firing on the city on Monday night, van Uhm said.
"But there is a limit to what can be achieved with airpower to stop fighting in a city. We are taking every precaution to avoid causing civilian casualties by our own air operations."
"What we are doing is attacking the regime's ability to supply and sustain these attacks ... not just in the area of Misrata but across the country."
NATO's senior military officer, Admiral Giampaolo Di Paola, told a briefing in Rome that NATO strikes had done "quite significant damage" to Gaddafi's heavy weaponry, but what he had left was "still considerable."
"Unfortunately, we still have not succeeded in neutralizing the other offensive capacity of Gaddafi, which comes from his use of weapons which are less powerful but are equally destructive and lethal, like mortars and rockets.
"Gaddafi is able to move them around inside the cities, where it is much more difficult to locate them and neutralize them without doing damage. This is the difficulty that the international community is debating at the moment."
UN APPEALS FOR CEASEFIRE
The United Nations appealed on Tuesday for a ceasefire in Misrata, saying at least 20 children had been killed in attacks by government forces on rebel-held parts of the city.
The city has been under siege by government troops for more than seven weeks and rebel spokesmen, citing hospital records, say hundreds of people have been killed.
Aid groups say conditions are worsening in the city of 300,000, with a lack of food, medicines and other basic items.
Van Uhm said he saw no need for deployment of ground troops to protect aid deliveries, which the European Union has offered to provide but which the United Nations has yet to request.
He accused Gaddafi's forces of shelling Misrata "indiscriminately" and said they had complicated NATO's efforts by hiding tanks in civilian areas and using civilians as human shields.
Misrata's plight has highlighted the limitations of a NATO-led air campaign designed to keep Gaddafi's forces out of the air and prevent attacks on civilians.
Many NATO members refuse to go beyond enforcing a U.N.-mandated no-fly zone to attack Gaddafi's forces, despite the urging of the United States, France and Britain, which all want to see Gaddafi removed from power.
Analysts say NATO may have no choice but to escalate its Libyan war effort and use helicopters or naval gunfire to end bloodshed in Misrata and break the military stalemate.
Van Uhm declined to comment when asked about the possibility of using helicopters and naval bombardments, but said "overall we have the necessary assets to carry out the mission."
NATO officials have said the NATO mission is short of about 10 aircraft and at a meeting of alliance foreign ministers last week, the United States and other NATO allies rebuffed French and British calls for them to do more in the air campaign.
Van Uhm said NATO now had "more assets" than Friday, but declined to give details.
(Additional reporting by Gavin Jones in Rome; Editing by Andrew Heavens)