ROME—NATO is having trouble destroying mortars and rockets fired by Moammar Gadhafi loyalists at the besieged rebel city of Misrata, the organization’s top military official said Tuesday, citing the alliance’s mandate that does not allow it to use ground forces in Libya.

The city has been under attack for seven weeks, and the New York-based Human Rights Watch has accused the regime’s forces of launching indiscriminate assaults on residential neighbourhoods.

Admiral Giampaolo Di Paola, the chairman of the alliance’s military committee, told reporters in Rome that even though NATO operations have done serious damage to the Libyan regime’s heavy weaponry, what Gadhafi has left is “still considerable.”

Asked if more NATO air power and bombing are needed, Di Paola said any “significantly additional” allied contribution would be welcome. Given NATO’s humanitarian mandate reflecting the UN Security Council Resolution on Libya, which does not allow ground forces, it’s tough to stop the regime’s firepower on Misrata, Di Paola told reporters in Rome.

For NATO “to go inside the city and take out these (weapons), which are easily mobile and easy to hide, we would cause heavy civilian damage,” Di Paola added.

Meanwhile, the leader of the Libyan rebels’ transitional government, Mustafa Abdul-Jalil, was in Rome for talks with top Italian officials, including on ways to help Libyan people in Misrata and other besieged cities.

Italian Foreign Minister Franco Frattini said after talks with Abdul-Jalil that the international community will look at new measures to help Libya’s besieged cities during a meeting next month in Rome.

Such measures might include supplying the rebels with technical instruments such as radars or systems to intercept and block telecommunications. Rome remains opposed to sending ground troops, Frattini said.

Abdul-Jalil’s visit also included meetings with the country’s president, prime minister and a group of businessmen with interests in Libya. He travels to Paris for talks President Nicolas Sarkozy on Wednesday.

Italy and France, along with Qatar, have recognized the Libyan National Transitional Council. Abdul-Jalil said Tuesday “there will be strong co-operation first and foremost with Italy, Qatar and France; after them come all our other friends, such as the United States and the United Kingdom.”

Russia, which abstained in the United Nations vote that sanctioned the military operation, has continued to voice concern about civilian casualties and excessive use of force since the operation in Libya began.

Foreign Minister Sergei Lavrov insisted during a visit to Belgrade, Serbia on Tuesday, that the “most urgent step that must be taken is the immediate cease fire.” The opposition in both Libya and Yemen will not negotiate because “they expect help from abroad,” he insisted.

“It is of principal importance that everybody should support the start of dialogue and not confrontation,” Lavrov said.

In Geneva, The World Food Program said Tuesday it has managed to secure safe passage for aid deliveries into parts of western Libya, after the government indicated it would respect a humanitarian corridor agreed upon by the UN food agency and the Libyan Red Crescent.

The UN agency had signed an agreement with the Libyan Red Crescent to establish a humanitarian corridor, and “we received an indication that the government did not have any objection,” spokeswoman Emilia Casella said.

Separately, the UN humanitarian chief said Monday she was assured the UN would be permitted to visit Misrata and other towns to assess the humanitarian need.

The UN refugee agency said Tuesday that thousands of Libyans are fleeing to southern Tunisia every day to escape worsening fighting in Libya’s Western Mountains region. UNHCR spokesman Firas Kayal in Tunisia said some 10,000 people, many of them ethnic Berbers, have arrived in the Dehiba area of southern Tunisia in the last ten days.