Vital United Nations relief assistance has arrived by sea and by air in the Libyan cities of Benghazi and Misrata in the past couple of days, as fighting continues to rage between the Government and rebels seeking the ouster of Colonel Muammar Al-Qaddafi.

In eastern Libya, a plane chartered by the UN High Commissioner for Refugees (UNHCR) arrived Monday in Benghazi carrying hospital tents, kitchen sets and plastic sheets for shelter.

This is the first UN humanitarian flight to land in the rebel-held city, according to the agency, which said the airlift also brought cars and equipment for UNHCR to support the opening of an office in Benghazi together with other UN agencies.

Meanwhile, a ship chartered by the UN World Food Programme (WFP) has delivered more than 500 tons of food assistance, three ambulances, medical supplies and other relief items to Misrata.

It is the second time this month a WFP-chartered vessel has delivered aid to the people of the north-western city, which has been the scene of continuous fighting this year between military forces allied to the Qadhafi regime and opposition groups.

"The humanitarian situation is growing increasingly urgent," Secretary-General Ban Ki-moon warned Tuesday, adding that the priority is to protect civilians.

He told reporters after briefing the Security Council in a closed-door meeting that the Libyan regime has lost both legitimacy and credibility, particularly in terms of protecting its people and addressing their legitimate aspirations for change.

Diplomatic efforts aimed at securing a ceasefire and achieving a political solution are continuing, Ban added, noting that his Special Envoy, Abdel Elah al-Khatib, will travel once again to Benghazi on Friday.

As fighting continues to rage in Misrata, the families recently evacuated by boats to Tobruk describe a "catastrophic" situation with many having lived in fear of indiscriminate shelling, UNHCR spokesperson Andrej Mahecic told a news conference in Geneva.

"Many houses and buildings have been destroyed and some families had to move several times. Parts of Misrata have had neither electricity nor water. Sniper fire, street clashes and shelling have prevented people from venturing outside of their homes to get food and medicine," he said.

"Families evacuated from Misrata also say they have been hiding in their homes for the past two months before seizing the opportunity of a lull in fighting to get to the harbor and board a boat," added Mahecic.

Evacuees also told UNHCR staff that in some neighborhoods in Misrata, pregnant women gave birth in their homes as it would have been too dangerous to make the trip to the hospital.

The agency also reported that an estimated 30,000 Libyans have fled their homes in western Libya and crossed into southern Tunisia over the past three weeks, many of them ethnic Berbers.

A UN inter-agency humanitarian team travelled from the Tunisian border to the Libyan capital, Tripoli, on Sunday with the goal of re-establishing an international presence there and to review humanitarian needs. The team is also discussing humanitarian access in the west with the Libyan authorities.

As of Tuesday, the $310 million aid appeal for Libya is 42 per cent funded, with $129 million received and $1.4 million pledged, according to the UN Office for the Coordination of Humanitarian Affairs (OCHA).

The appeal covers assistance for a three-month period in areas such as food security, nutrition, health care, water and sanitation and shelter.

WFP Tuesday voiced concerned about access to food for people stranded in areas heavily affected by the fighting, as well as about food security and the future of the public food distribution system in Libya as food stocks in the country are being consumed without replenishment.

"The longer the conflict lasts, the more likely that the number of those in need of food assistance will increase," the agency stated in a news release.

A recent inter-agency mission found that food stocks in the eastern parts of the country are not being replenished at normal rates and the current stocks are enough for up to two months only, WFP said, warning of a potential massive food availability problem for all of eastern Libya if the country's import capacity is not restored quickly.

The fighting in Libya started out as protests against the Qaddafi regime, and is part of a broader pro-democracy movement across North Africa and the Middle East that has led to the downfall of long-standing regimes in Tunisia and Egypt.