Tripoli: Libya offered truce to the visiting United Nations (UN) special envoy Abdul-Ilah al-Khatib to the country in return for an immediate NATO ceasefire, as the revolt entered its fourth month.

After meeting Khatib, Prime Minister Baghdadi Mahmudi said Libya is keen for "an immediate ceasefire to coincide with a stop to the NATO bombardment and the acceptance of international observers."

Meanwhile, the head of Britain's armed forces said NATO should widen its bombing campaign to ensure Gaddafi is unable to cling to power, while Pope Benedict XVI called for negotiations to end the violence.

However, Mahmudi added that his country was committed to the unity of its territory and people and that Libyans had the right to "decide on their internal affairs and political system through democratic dialogue away from the bombing threat."

He accused NATO, which has been in charge of enforcing a UN-mandated no-fly zone over Libya, of "abuses and violations" including "political assassinations, the unjust maritime siege, bombing of civilian sites and destruction of infrastructure."

Several loud explosions shook the east of Tripoli and columns of smoke rose into the sky after Khatib arrived in the country.

A state news agency reported "human losses and material damage" after NATO struck "military and civilian" sites in Zuara, west of Tripoli. A NATO spokesman confirmed the alliance targeted military equipment in the city.

"I can confirm we did attack in the area of Zuara military equipments used by Kadhafi forces to target civilians," he said.

UN chief Ban Ki-moon said this week he had urged Mahmudi to halt attacks on civilians immediately and called for "immediate and verifiable  negotiations towards the peaceful solution of the conflict and unimpeded access to humanitarian workers."

General David Richards, Britain's chief of the defence staff, meanwhile told Britain's news daily that more military action was needed against the Libyan strongman.

"The vice is closing on Gaddafi, but we need to increase the pressure further through more intense military action," he said.

The general said he wanted NATO member states to support targeting of Gaddafi's regime, not just targets which pose an immediate threat to civilians, such as tanks and artillery.