A view of the destruction of a UNESCO-listed heritage site in the old city of the Yemeni capital, Sanaa. (Mohammed Huwais/AFP/Getty Images)

In an ominous sign for diplomatic efforts to end the fighting in Yemen, U.N.-led peace talks in Geneva appeared to be delayed for a second day Monday.

The delegation representing the Shiite Houthi rebel movement and parties allied with it left the Yemeni capital, Sanaa, on Sunday, after an unspecified delay a day earlier. By Monday afternoon, the delegation’s plane was en route to the Swiss city after a long stopover in Djibouti, according to the United Nations.

The talks, initially scheduled for Sunday, are designed to end months of war in the Arabian Peninsula country. The conflict escalated in March, when a coalition led by Saudi Arabia began targeting the rebels with airstrikes. Since the Saudi-led intervention, the United Nations estimates that the fighting has killed more than 2,500 people and displaced more than half a million. Aid groups warn of a humanitarian disaster in Yemen, home to an estimated 26 million people.

Speaking to reporters in Geneva ahead of the scheduled talks, U.N. Secretary General Ban Ki-moon called for a two-week “humanitarian pause” in the fighting.

During the Geneva meetings, the Houthi-led delegation and officials representing the rival Yemeni authority of President Abed Rabbo Mansour Hadi are expected to meet separately with mediators. U.N. officials hope the discussions will lead to direct peace negotiations between the warring parties, although expectations for a swift breakthrough are low.

Officials under Hadi’s authority demand that the Houthis must withdraw from cities they have captured before any agreement can be reached. But the rebels are continuing to expand their control, capturing the capital of the northwestern Jawf province on Sunday.

In February, the rebels toppled Hadi’s government, which relocated to Saudi Arabia and backs the coalition’s air war against the Shiite insurgents.

Saudi Arabia, a Sunni powerhouse, views the Houthis as proxies of Shiite-led Iran, a nemesis.

The U.N.-chartered aircraft carrying the Houthi-led delegation left Djibouti for Geneva on Monday and is set to arrive in the Swiss city early Tuesday, according to the United Nations. The reason for the lengthy stop in the East African nation was not clear.

The Associated Press earlier reported that Egypt, a member of the Saudi-led coalition, denied the plane permission to land in Cairo.

But Mohammed al-Bukhaiti, a senior Houthi political official, called reports of Egyptian obstruction “rumors.” The plane was never scheduled to stop in the Egyptian capital, he said, speaking from Sanaa.

Also attending the Geneva talks are allies of Ali Abdullah Saleh, a former Yemeni president who has sided with the Houthis. Saleh still controls powerful units in Yemen’s military that have played an important role in helping the Houthis seize territory.

Naylor reported from Beirut.

Read more:

Yemen conflict’s risk for Saudis: ‘Their Vietnam’

In Yemen, children — possibly thousands of them — join fight

Fighting in Yemen is creating a humanitarian crisis

What it’s like to report on Yemen’s chaos