UNITED NATIONS — September was the deadliest month for civilians in war-torn Yemen this year but violence has lessened very recently and there are signs of hope, UN officials said Thursday.

UN envoy Martin Griffiths cautioned in a briefing to the Security Council, however, that the hopeful signs “are fragile.”

He pointed to the very recent reduction of violence in Yemen’s mainly rebel-controlled north, the “volatile” situation in southern Yemen “but with a tenuous calm” in its main city, Aden, and “a growing generosity of spirit between the parties,” including the freeing of some detainees and prisoners and desperately needed oil ships being allowed into the main port of Hodeida.

“These are small signs perhaps in a frightening season but something for us to nurture,” Griffiths said by video from the Saudi capital, Riyadh.

UN humanitarian chief Mark Lowcock told the council that “September was the deadliest month for civilians so far this year, with reports of 388 killed or injured due to conflict across the country.”

“That’s an average of 13 people every day,” he said.

Lowcock cited some of many “gruesome examples” including four children killed in the detonation of unexploded ordnance, airstrikes killing 22 civilians in a mosque and family home, and the fourth airstrike on a UN-supported water system serving 12,000 people.

The conflict in Yemen began with the 2014 takeover of the capital, Sanaa, by Iran-backed Houthi Shiite rebels who control much of the country’s north. A Saudi-led coalition allied with Yemen’s internationally recognized government has been fighting the Houthis since 2015.

The fighting in the Arab world’s poorest country has killed thousands of civilians and created the world’s worst humanitarian crisis, leaving millions suffering from food and medical care shortages and pushing the country to the brink of famine.

Lowcock told the council that Yemen remains “the world’s worst humanitarian crisis and the largest relief operation,” with more than 250 relief agencies, mostly Yemeni, working with the UN and reaching 12 million people across the country every month.

While the situation on violence “is a bit better,” he said, there are still “more than 30 active front lines” and “we can only hope that recent steps towards de-escalation … will continue.”

UN envoy Griffiths said that in the south, which saw a violent attempt to take over government institutions in August, “there has been no large-scale fighting in the areas of dispute.”

He told the council he had hoped an agreement could have been announced Thursday resolving issues between the internationally recognized government and separatists that would end the power struggle in Aden.

Talks in Jeddah, Saudi Arabia, have made “very significant progress,” Griffiths said, and an agreement “may be well within reach.”

He welcomed last month’s initiative by the Houthis to suspend all drones and ballistic missile attacks on Saudi Arabia, “and I also welcome the reduction of violence that followed that announcement.”

“Since the beginning of October, the number of airstrikes has reduced considerably across Yemen,” Griffiths said. “And I am obviously encouraged by that. This is, however, a very recent and obviously a very fragile gain, but it’s certainly a step in the right direction.”

Griffiths’ goal remains to get representatives from the government, the Houthis and the south around the same table to negotiate an end to the war and a political deal that unites the country — but that still remains a distant goal.