WASHINGTON — The United States and other world powers said Monday that they will boost the fight against the Islamic State in Libya by sending arms to aid the country’s internationally recognized government.
The move followed talks in Vienna involving Secretary of State John Kerry and other diplomats. It reflects worries over a widening presence of Islamic State militants in Libya, which has been divided between rival administrations and plagued by increased lawlessness.
In February, President Obama urged greater efforts to keep the Islamic State from ‘‘digging in’’ across Libya.
Supplying arms to allied forces in Libya would require United Nations approval because of the UN arms embargo against Libya that seeks to prevent weapons from falling into the hands of Islamist militants and other factions. However, all five permanent members of the Security Council have approved the plan.
A joint communique issued in Vienna said the permanent members of the Security Council and more than 15 other nations pledged readiness to provide training and equipment to Libyan government forces. They would be funneled to the central government based in the eastern city of Tobruk.
Another major complication is identifying which groups will align themselves with the unity government, formed earlier this year after UN-brokered talks in attempts to bring together the rival factions.
US Special Operations troops have been stationed at two outposts in eastern and western Libya since late 2015, tasked with lining up local partners in advance of a possible offensive against the Islamic State, US officials said last week, speaking on condition of anonymity to discuss a sensitive mission.
A US air attack in February targeted a suspected Islamic State camp, killing at least 40 people including a senior operative, Noureddine Chouchane, who was linked to attacks against Western tourists in neighboring Tunisia.
The Islamic State and other militant groups are gaining footholds in the Libya’s lawless regions.
Aiming at once to shore up the fragile government, and prevent Islamic State fighters and rival militias from further gains, the United States, the four other permanent UN Security Council members, and more than 15 other nations said they would approve exemptions to a UN arms embargo to allow military sales and aid to Libya’s so-called Government of National Accord.
In the communique, the nations said that while the broader arms embargo will remain in place, exemptions will be made “to respond to the Libyan government’s requests for training and equipping’’ government forces.
‘‘We will fully support these efforts while continuing to reinforce the UN arms embargo,’’ the communique said.
The aim is to give the internationally recognized central government of Libya more muscle in fighting the Islamic State. It would also give the government battle a militia group to the east that is claiming governing power.
The plan will boost the government’s efforts to consolidate power and regain control over Libyan state institutions such as the central bank and national oil company. However, it also comes with risks, including the possibility that the arms may be captured or otherwise taken by the Islamic State or other groups.
Kerry called the plan ‘‘a delicate balance,’’ according to the Associated Press, which first reported the Vienna deal.
‘‘But we are all of us here today supportive of the fact that if you have a legitimate government and that legitimate government is fighting terrorism, that legitimate government should not be victimized by [the embargo],’’ he told reporters.
Libya’s prime minister, Fayez al-Sarraj, said his government would soon submit a weapons wish list to the Security Council for approval. ‘‘We have a major challenge ahead of us,’’ in fighting extremists, he said. ‘‘We urge the international community to assist us.’’
Before the meeting, Foreign Minister Frank-Walter Steinmeier of Germany outlined the high stakes at hand.
‘‘The key question is whether Libya remains a place where terrorism, criminal human smuggling, and instability continue to expand, or if we are able, together with the government of national unity, to recover stability,’’ he told reporters.
The challenges are daunting.
Libya descended into chaos after the toppling and death of Moammar Gadhafi five years ago and turned into a battleground of rival militias battling for powers. More recently, the power vacuum has allowed Islamic State radicals to expand their presence, giving them a potential base in a country separated from Europe only by a relatively small stretch of the Mediterranean Sea.
Another concern for Europe is the threat of an influx of refugees amassing in Libya, now that the earlier route from Turkey into Greece has been essentially shut down.
Foreign Secretary David Hammond of Britain said his government had received a request from the Libyan government to bolster its Coast Guard — a project that will “address Libyan concerns about smuggling and insecurity on their border, but will also address European concerns about illegal migration.’’
In Libya on Monday, the UN-established presidency council gave the go-ahead for 18 government ministers to start work, even though they have not received backing from the Parliament.
