The United Nations said Tuesday that the last of its international staffers have now left Yemen as the U.N. human rights chief warns of a "total collapse" in the Arab world's poorest country.

The deputy spokesman for the U.N. secretary-general, Farhan Haq, said the remaining 13 international staffers were now out and that the U.N. will do what it can with the hundreds of local staffers who are still there.

Even the U.N. envoy to Yemen, Jamal Benomar, has left the country.

Haq said the U.N. had "well over 100" international staff in Yemen just a week ago, with most evacuated over the weekend. He called it a temporary relocation and said staffers had been moved to Ethiopia and Jordan.

The U.N. human rights office in Geneva said at least 93 civilians have been killed and 364 wounded in five Yemeni cities in the past five days as Saudi-led airstrikes pound advancing Shiite rebels.

The overall figures are likely much higher. U.N. officials called on all sides to protect civilians from harm in the fighting.

"We are concerned about any escalation of this conflict," Haq said.

He also noted that all sides in Yemen are being encouraged to return to the negotiating table for U.N.-led peace talks.