"Libya needs a decisive stance from the international community to help us build our national army's capacity and this would come through a lifting of the embargo on weapons so that our army can receive material and weapons so as to deal with this rampant terrorism," the foreign minister said.
Dairi emphasized that he was not seeking an international military intervention, but stressed that there was no time to lose to equip the Libyan army to confront the emboldened extremists.
As Libya pressed for urgent military aid, UN envoy Bernardino Leon said political efforts to broker a deal on forming a unity government able to address the threat from extremists could soon yield results.
"I am hopeful that a political agreement can be reached soon. The differences between the parties are not insurmountable," Leon said.
Egypt was pushing for a UN draft resolution easing restrictions on weapons sales to Libya, but Western diplomats expressed reservations, saying a political deal must be the priority.
There was no draft resolution slated for a vote at the council meeting on Wednesday.
- Fueling the fire -
Egyptian Foreign Minister Sameh Shoukry said Jordan would circulate later Wednesday a draft text on behalf of Arab nations that calls for easing the arms embargo.
The measure would also set up a naval blockade to prevent weapons shipments from reaching the jihadists.
"While the political solution is an absolute necessity, it is not an alternative to militarily confronting terrorism," Shoukry told the council. He said the draft resolution would be discussed in the coming days.
The UN embargo was imposed in 2011 when Libya descended into violence after the uprising against Moamer Kadhafi.
Western powers are wary of committing to an easing of the arms ban in Libya, which is still awash with weapons and where rival militias are battling for control of its cities and oil wealth.
A council diplomat said lifting the arms embargo would be tantamount to pouring fuel on the Libyan fire.
Libya has two rival governments and parliaments, one recognized by the international community and the other with ties to Islamists.
A US-led coalition is carrying out air strikes against IS targets in Syria and Iraq, and Egyptian officials have suggested they should be expanded to Libya.
Libya's neighbor Tunisia said it too opposed military intervention, instead calling for a political solution.
That echoed a statement Tuesday by the United States, Britain, France, Germany, Italy and Spain that an ongoing UN effort to get Libya's warring sides to agree on a unity government was the "best hope" for peace.
- Islamist threat -
Libya has descended into chaos since the 2011 revolt, with the internationally recognized government forced to flee to the country's east and militias in control of Tripoli and other main cities.
Some militias have pledged allegiance to the Islamic State group, which this week released a video of the gruesome mass beheadings of 21 Coptic Christians.
"We are dealing with a phenomenon that is now becoming a front, stretching from the Middle East to North Africa, covering the Mediterranean region and the Sahel," the Libyan foreign minister told the council.
The country's main militias, including the Islamist-backed Fajr Libya coalition that has declared a rival government in Tripoli and has been involved in the peace talks, have not linked up with IS jihadists.
But Italian Foreign Minister Paolo Gentiloni warned of the threat of such an alliance.
"There is an evident risk of an alliance being forged between local groups and Daesh, and it is a situation that has to be monitored with maximum attention," Gentiloni said, using an Arabic acronym for the Islamic State organization.
The chaos in Libya has contributed to a dramatic increase in the number of migrants attempting to travel across the Mediterranean to Europe.
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