The office of the U.N. human rights chief said Tuesday that 151 civilians have been killed in fighting in Yemen over two weeks in September, taking the civilian death toll to 2,355 over the last six months.

The Office of the High Commissioner for Human Rights (OHCHR) cited both sides of the conflict, including a Saudi-led coalition supporting Yemen's government in exile, and Shia rebels, known as Houthis. Spokesman Rupert Colville pointed to coalition airstrikes and “indiscriminate” shelling in residential areas.

OHCHR wants the coalition and Yemen's government to allow “independent and impartial” investigations in Yemen.

The agency's latest count, which dates to Sept. 24, does not include casualties from an alleged coalition airstrike of a wedding party in Taiz province that U.N. and Yemeni officials say may have killed more than 130 people.

The Saudi-led coalition has denied responsibility for the attack.

Details about the strike, which took place Monday, were sketchy but a U.N. official said that if confirmed, the high death toll would make it one of the deadliest incidents in the conflict.

At least 80 women were among the dead, said Yemeni medical officials, who work in the province and have been neutral in the conflict that has torn their country apart. They spoke on condition of anonymity because they were not authorized to speak to reporters.

The coalition targeting Yemen's Shia rebels apparently struck the wedding party by mistake in Al-Wahga, a village near the strategic Strait of Bab Al-Mandab, according to Yemeni security officials.

U.N. Secretary-General Ban Ki-Moon has condemned the airstrike and called on all parties involved in the conflict “from inside and outside the country, to immediately cease all military activities.”

But Saudi coalition spokesman Brigadier-General Ahmed al-Asseri said there had been no air operations for three days in the area where the attack occurred so “this is totally false news.”

He added that the coalition would concede a mistake if it made one, but Yemen's conflict was chaotic with a grab bag of armed groups active, and that civilians sometimes could not differentiate between cannon, mortar and rocket fire.

In Geneva, Colville said it had a team on the ground in Yemen trying to verify details of the wedding party bloodshed.

“The [Yemeni] government in exile seemed to have acknowledged it and said it was a mistake. … I don't think we have much doubt that this incident took place and it is a grave incident," Colville told a news conference.

He also said the coalition’s naval blockade of Yemen’s main seaports was exacerbating a humanitarian crisis in Yemen. World Food Program spokeswoman Bettina Luescher said 10 of Yemen’s 22 governorates were so short of food that famines were looming.

The United States is the main arms supplier to the Gulf Arab coalition. In April, U.S. officials said Washington was expanding intelligence-sharing with Saudi Arabia to provide more details about potential Houthi targets.