The U.N. envoy to Yemen warned Thursday that the impoverished country is at a crossroads between "civil war and disintegration" and a successful political transition.

Jamal Benomar's grim briefing to the U.N. Security Council followed a similar statement from U.N. Secretary-General Ban Ki-moon that "Yemen is collapsing before our eyes" and the international community should not stand by and watch.

The U.S., Britain and France moved to close their embassies Wednesday, signaling a belief that conditions in Yemen would only deteriorate further as the Houthi rebels, who have taken over the central government and nearly half the provinces, try to expand their control.

The rebels are suspected of being backed by Iran in their advance through Sunni Muslim-majority Yemen. The Houthis, who are Shiites, deny links to Iran, a Shiite country.

Benomar told the council that instability in Yemen is creating conditions for al-Qaida, a Sunni extremist terror group, to establish a foothold in more parts of the country. His remarks came just hours after Yemeni military officials said al-Qaida militants seized control of an important army base in the south. Yemen is home to what is considered the most dangerous branch of al-Qaida.

In January, the Houthi rebels put U.S.-backed President Abed Rabbo Mansour Hadi and his Cabinet ministers under house arrest, leading to their resignations. Subsequently, the Houthis dissolved parliament and declared they were taking over the government.

In his statement Thursday, Ban demanded freedom of movement for Hadi.

Speaking from Yemen, Benomar said he is "in the middle of delicate negotiations" daily with parties involved in the conflict. "We are navigating through many minefields," he said.

In a sign of the uncertainty on the ground, Benomar downgraded his assessment of the talks, departing from "good progress has been made" in his prepared text to say "reasonable progress has been made."

Yemen's representative urged the Security Council to take "rapid measures." Qatar, representing the Gulf Coordination Council of Arab states on the Persian Gulf, warned that if the council doesn't react quickly enough, it could encourage the Houthi rebels — and perhaps al-Qaida — to go even further in threatening regional security.

The U.N. secretary-general also warned of "increasing secessionist tendencies" in southern Yemen, which was once a separate nation, and of a humanitarian crisis where 61 percent of the country's population is in need of aid.

"We must do everything possible to help Yemen step back from the brink and get the political process back on track," Ban said. He said the first focus is on "helping the Yemeni people to re-establish a legitimate government authority as soon as possible."

UN-AP