Europe is ready to send an armed force to Libya to ensure delivery of humanitarian aid, and Britain said Tuesday it will dispatch senior military officers to advise the opposition — signs that Western nations are inching closer to having troops on Libyan soil.

The bid by the European Union to deploy the armed force to escort humanitarian aid drew an immediate warning from Moammar Gadhafi's regime that this would be tantamount to a military operation.

The new tactics seem to have been spurred by the continued deadlock after two months of fighting between Gadhafi's army and rebel forces. There has also been growing international concern over the fate of the besieged rebel city of Misrata, where NATO admits it is unable to halt heavy shelling by Gadhafi's forces with airstrikes alone.

Misrata, Libya's third-largest city, has been under siege for nearly two months, with rebels holding on to seaside positions in the port area. Libyan troops have pounded the city with shells and rockets in recent days.

On Tuesday, rebels and troops clashed in central Misrata, and explosions and gunfire were heard. NATO's strikes only targeted radars and air defences, said Abdel-Salam, a resident who identified himself only by his given name for fear of retaliation. Hospitals are filled with the wounded, and 120 patients need to be evacuated, the World Health Organization said.

A rebel fighter mans a Grad rocket launcher in the front line along the western entrance of Ajdabiyah on Tuesday. (Amr Abdallah Dalsh/Reuters)

NATO officials acknowledged that they are having trouble destroying Gadhafi's mortars and rocket launchers from the air, for fear of inadvertently harming civilians in such strikes.

"It's not a conventional war," Admiral Giampaolo Di Paola, chairman of NATO's military committee, said Tuesday. He would not say just how much of the regime's firepower has been eliminated or put out of action by NATO's operations so far.

The fighting in Libya has been deadlocked for the past month. Gadhafi is holding on in the west, while the rebels control the east. NATO airstrikes have kept Gadhafi loyalists in check, but the rebels, a poorly trained group with little military experience, have not been able to score military gains, either.

As the allies seek ways to break the battlefield stalemate, British Foreign Secretary William Hague said Britain will send a team of up to 20 senior military advisers to the rebel stronghold of Benghazi to help organize the country's haphazard opposition forces.

Hague insisted the advisers would not be involved in supplying weapons to the rebels or in assisting their attacks on Gadhafi's forces. He said the advisers would work with British diplomats already co-operating with the National Transitional Council, the political wing of the rebel movement, which has been officially recognized by Italy, France and Qatar.

Britain has already sent non-lethal support, such as 1,000 sets of body armour and 100 satellite phones.

The EU, meanwhile, said it could deploy an armed force to Libya within days to ensure the delivery of humanitarian supplies, said Michael Mann, a spokesman for EU foreign policy chief Catherine Ashton.

A rebel fighter hits a picture of Libyan leader Moammar Gaddafi near Ajdabiyah on Tuesday. (Amr Abdallah Dalsh/Reuters)

Mann said a "concept of operations" has been approved by the European Union's 27 countries, outlining various possible courses of action. But Mann said the details of the operation, including how many people and what equipment would be needed, would await the specifics of any UN request.

The EU has no standing army, and the personnel and equipment would have be donated by member countries.

Ashton made the offer of military aid to protect humanitarian groups on April 1, but so far no UN request has been forthcoming.

Over the weekend, the UN reached agreement with Gadhafi's government on carrying out aid operations in areas of Libya he controls. A key destination for such aid would be Misrata.

Libyan Deputy Foreign Minister Khaled Kaim, asked about the possibility of foreign troop escorts of aid convoys, said "if there is any deployment of any armed personnel on Libyan ground, there will be fighting, and the Libyan government will not take this as a humanitarian mission" but as a military one. He said the Libyan government has repeatedly offered to help humanitarian agencies do their work.

Kaim also said NATO airstrikes have knocked out telecommunications in the central Libyan towns of Sirte, Brega and Ras Lanouf. He alleged the strikes were meant to help the rebels advance westward, into areas controlled by Gadhafi's forces.

Gadhafi's weaponry 'still considerable': NATO

NATO's Di Paola said in Rome that even though NATO operations have done "quite significant damage" to the Libyan regime's heavy weaponry, what Gadhafi has left is "still considerable."

Rebel fighters pray at the front line near Ajdabiya on Tuesday. (Amr Abdallah Dalsh)

Asked if more NATO air power and bombing are needed, Di Paola said any "significantly additional" allied contribution would be welcome.

World Food Program spokeswoman Emilia Casella says the UN agency signed an agreement with the Libyan Red Crescent to establish a humanitarian corridor in western Libya and "we received an indication that the government did not have any objection."

Casella said WFP trucks are already bringing food to feed 50,000 people for one month. The food will be distributed by the Libyan Red Crescent in Tripoli, Zintan, Yefrin, Nalut, Mizda, Al Reiba and Zawiya.

Separately, the UN humanitarian chief said she was assured the UN would be permitted to visit Misrata and other towns to assess the humanitarian need. Her agency said it was cool to the European Union idea to deploy an armed force to escort humanitarian aid, saying it was still able to use civilian assets on the ground.