U.S. Ambassador Nikki Haley sharply criticized the U.N. peacekeeping commander in Lebanon on Friday, saying he is "blind" to the spread of illegal arms and reiterating a call for the force to do more about it. He says there's no evidence it's actually happening.

With the peacekeeping mission up for renewal next week, the United States has been pressing to step up efforts to tackle what Haley describes as a "massive flow of illegal weapons" to Hezbollah-dominated southern Lebanon, where neighboring Israel has long complained that the militant group operates with impunity.

But the peacekeeping commander, Maj. Gen. Michael Beary, pushed back this week on U.S. and Israeli criticism. The Irish general told The Associated Press that his force has no evidence of weapons being illegally transferred and stockpiled in the area, and that "if there was a large cache of weapons, we would know about it."

But Haley said there's plenty of evidence including Hezbollah's own boasts and Beary displayed "an embarrassing lack of understanding of what's going on."

"He seems to be the only person in south Lebanon who is blind to what Hezbollah is doing," she said, adding that his view of the situation "shows that we need to have changes" in the mission.

Asked about her comments, U.N. spokesman Stephane Dujarric said the organization has full confidence in Beary's work and noted that debate over the mission would play out in the Security Council.

Secretary-General Antonio Guterres told the council in a letter that he intends to look at ways for the peacekeeping force to "enhance its efforts," but he stressed that it's primarily the Lebanese military's responsibility to ensure the south is free of unauthorized weapons.

The peacekeeping mission, known as UNIFIL, dates to 1978. It was expanded after the 2006 war between Israel and Hezbollah so that peacekeepers could deploy along the border with Israel to help Lebanese troops extend their authority into the south for the first time in decades.

Haley has said the United States wants "significant improvements" to the peacekeeping force, though she said Friday that doesn't mean changing the overall mandate but rather some language.

"It's time the Security Council puts teeth in the UNIFIL operation," she said. "We don't need to be giving terrorists a pass."

Discussions are ongoing, and it's not clear how keen the council will be on the U.S. approach.

Russia's U.N. Ambassador, Vassily Nebenzia, said Wednesday that the mandate should be renewed as is and added that other countries had voiced the same view during a council discussion.

French Deputy Ambassador Anne Gueguen, whose country is in charge of drafting a proposed renewal, said Wednesday it was "of paramount importance for the stability of Lebanon and the region, and in the best interest of all, that UNIFIL keeps its mandate and is in a position to fulfill it."