UPDATE 4-U.N. chief meets eastern Libya commander as fighters close in on Tripoli

U.N. Secretary-General Antonio Guterres met eastern Libyan commander Khalifa Haftar in Benghazi on Friday in a bid to avert renewed civil war as his forces advanced on the capital Tripoli to challenge the internationally recognised government. The military thrust by Haftar's Libyan National Army (LNA), which is allied to a parallel administration based in the east, marked a dangerous escalation of a power struggle that has dragged on since the overthrow of Muammar Gaddafi in 2011.

LNA forces on Thursday took Gharyan, about 80 km (50 miles) south of Tripoli after skirmishes with forces allied to Tripoli-based Prime Minister Fayez al-Serraj. But they failed to take a checkpoint about 30 km west of the capital in a bid to close the coastal road to Tunisia. An LNA-allied militia withdrew overnight from so-called Gate 27, leaving it abandoned in the morning, a Reuters reporter said.

In another setback, forces allied to Tripoli took 145 LNA fighters prisoner in Zawiya, west of Tripoli, a western commander, Mohamed Alhudair, told Reuters. An LNA source confirmed 128 had been captured. Sixty vehicles had also been seized, Alhudairi said.

Meanwhile armed groups allied to the U.N.-backed Tripoli government moved more machinegun-mounted pickups from the coastal city of Misrata to Tripoli to defend it against Haftar's forces. The escalation surprised the United Nations, whose Secretary-General Guterres had been in Tripoli this week to help organize a national reconciliation conference planned for later this month.

Guterres, who spent Thursday night in the heavily fortified U.N. compound in a Tripoli suburb, flew to Benghazi and drove to Haftar's base, witnesses said. He earlier went to Tobruk, another eastern city, to meet Aguila Saleh, president of the House of Representatives, which is also allied to Haftar.

"My aim remains the same: avoid a military confrontation. I reiterate that there is no military solution for the Libyan crisis, only a political one," Guterres said on Twitter. On Thursday, Saleh welcomed the offensive. After the meeting with Guterres, his spokesman said they had discussed ways to end the crisis and the planned conference, without giving details.

INTERNATIONAL CONCERN Haftar enjoys the backing of Egypt and the United Arab Emirates, which see him as bulwark against Islamists and have supported him militarily, according to U.N. reports.

The UAE, however, joined Western countries in expressing its deep concern about the fighting. Germany called an emergency meeting of the U.N. Security Council due to the military escalation.

Russia said it was not helping Haftar's forces and it supported a negotiated political settlement that ruled out any new bloodshed. Former colonial power Italy, which lies across the Mediterranean from Libya, was very worried by the turn of events, Italian Deputy Prime Minister Matteo Salvini said.

"We need to throw water on the fire, not petrol on the fire. I hope that people, acting out of economic or business self-interest, is not looking for a military solution, which would be devastating," Salvini said. Tunisia has tightened control on its border with Libya in response to the renewed conflict, the defence ministry said.

The United Nations and Western countries were already trying to mediate between Serraj and Haftar, who met in Abu Dhabi last month to discuss a power-sharing deal. The conference the United Nations is helping to organize is aimed at forging agreement on a road map for elections to resolve the prolonged instability in Libya, an oil producer and transit point for refugees and migrants trekking across the Sahara with the aim of reaching Europe. (Writing by Ulf Laessing; Editing by Angus MacSwan)