TRIPOLI  -  Libya’s internationally-backed government is deploying forces in and around the capital, Tripoli, after renegade General Khalifa Haftar on Thursday ordered his eastern military forces to advance on the city, sparking fears of a major showdown with rival militias.

The UN Security Council has called for an emergency meeting on Friday to discuss the escalation in Libya’s years-long power struggle, as a number of foreign powers urged restraint.

Earlier on Friday, the private news agency reported that some troops of Haftar’s self-styled Libyan National Army (LNA) were pushed back from a security barrier by a militia in Zawiya, fewer than 30km from the capital.

On Thursday, Haftar’s forces took over Gharyan, a town 100km south of Tripoli. In an audio recording posted on the LNA’s media office Facebook page, Haftar described his forces’ move as a “victorious march” to “shake the lands under the feet of the unjust bunch”. “We are coming Tripoli, we are coming,” he said.

The oil-rich country, which has been in turmoil since the NATO-backed removal of its long-time ruler Muammar Gaddafi in 2011, has at least two rival administrations: the internationally-recognised government based in Tripoli, headed by Prime Minister Fayez al-Sarraj; and another in the eastern city of Tobruk, which is allied with Haftar.

The rising tensions come as the United Nations is preparing to hold a conference later this month in the southwestern city of Ghadames to discuss a political solution to prepare for long-delayed elections and avoid a military showdown. Interior Minister Fathi Bashagha told Al Jazeera that Haftar is making his move at an unprecedented time of calm.

“Why use weapons and force to terrorise the people of Libya, to kill them, and to force them to accept one thing only, which is to be ruled by a military dictator? What makes Mr Haftar a better candidate than other Libyans?” Bashagha said.

“We will not be subdued by any use of force by any side or any person. And if anyone is willing to use force against us we’re ready for sacrifice but we will not give up on democracy which we’ve always wanted from the beginning.”

In the audio recording, Haftar urged his forces to enter Tripoli peacefully and only raise their weapons “in the face of those who seek injustice and prefer confrontation and fighting”. He also told them not to open fire on any civilians or those who are unarmed. “Those who lay down their weapons are safe, and those who raise the white banner are safe,” he said. The advance by Haftar’s forces prompted UN Secretary-General Antonio Guterres, who was in Tripoli on Thursday for talks with Sarraj, to voice his “deep concern”.

“I want to make a very strong appeal, an appeal for all military movements to stop, an appeal for containment, calm and de-escalation, both military and political and verbal de-escalation,” Guterres told reporters. He was due to meet Haftar in eastern Libya later on Friday. Analysts say Haftar’s previous strategy has been to expand his control through forging alliances and buying off opposition, and that his military move is motivated by the upcoming talks. “Haftar would like to force the hand of the UN and those attending in a way that does not exclude him, fearing that this conference may start a whole new path for Libya in the next few years and that he may not be included in that process,” said Hafed Al Ghwell, a fellow at the Foreign Policy Institute of Johns Hopkins University.

On Wednesday, the LNA’s media centre said on Facebook that several units had headed “to the western region to cleanse it of the remaining terrorist groups”.