Airstrikes target Yemen's capital hours ahead of planned cease-fire

U.S. officials raised alarm Tuesday over an Iranian cargo ship that Tehran says is carrying humanitarian aid to Yemen.

The Saudi-led coalition has accused Iran of supplying Yemen's rebels, known as Houthis, with weapons. The White House said Tuesday that the ship, the Iranian Shahed, should divert course to nearby Djibouti where the United Nations is coordinating aid distribution.

There were concerns late Tuesday that the planned five-day cease-fire — set to take effect at 11 p.m. (4 p.m. EDT) to allow humanitarian relief supplies to reach beleaguered Yemenis — could fall apart, with both sides warning against continued attacks.

Coalition jets have pounded targets across Yemen since March 26 in a bid to oust Houthi rebels from Yemeni cities and restore exiled Yemeni President Abed Rabbo Mansour Had to power.

The military campaign has killed more than 1,400 people and displaced more than 300,000 civilians, according to the United Nations. International aid groups have warned of an impending humanitarian catastrophe if the fighting continues.

On Tuesday, Saudi-led airstrikes hit three weapons depots in the capital, Sanaa. Residents told the Reuters news agency that three airstrikes hit a base for army units loyal to the rebels just north of the city.

In the southern port of Aden, witnesses told Reuters that the alliance bombed Houthi positions and that local armed groups were fighting the rebels in the vital port city and throughout the south.

The airstrikes Tuesday came one day after intensified coalition air raids pounded targets in Sanaa — notably suspected weapons depots on the city's outskirts — and the Houthis claimed to have downed a Moroccan fighter jet in the north.

The strikes in Sanaa on Monday killed 89 people and injured 300 others, according to a Health Ministry official in the capital.

An air attack on one weapons cache in eastern Sanaa sent a massive fireball and towering plume of smoke into the sky over the city and set off a series of secondary explosions that echoed across the capital for more than an hour, residents said.

The new United Nations envoy to Yemen, Ismail Ould Cheikh Ahmed, arrived in Sanaa on Tuesday to coordinate aid distribution and work toward negotiating a political solution, the Houthi-run SABA news agency reported.

The agency said Ahmed would meet with political leaders and that he called for unconditional dialogue between Yemeni factions to end the conflict.

On Tuesday, the U.N. refugee agency, UNHCR, said it was preparing to distribute blankets and other aid to 60,000 people from Yemen's Red Sea port of Hodeida. The agency said it was also working to airlift 300 tons of aid to the capital if the truce holds.

Due to severe fuel shortages, many people have fled dangerous areas on foot.

"Hundreds of thousands of people across Yemen are struggling to meet their basic needs and are in desperate need of help," UNHCR spokesman Adrian Edwards said in a statement.

New York-based Human Rights Watch said Monday that an air, naval and land blockade by the coalition is "keeping out fuel needed for the Yemeni population's survival, in violation of the laws of war."

"It is unclear how much longer Yemen's remaining hospitals have before the lights go out," said Joe Stork, the group's deputy Middle East and North Africa director.

Other aid groups have warned that Yemen's hospitals are quickly running out of supplies.

Saudi officials have warned that the cease-fire could be called off if rebel offensives continue.

In response, a Houthi-appointed military spokesman, Brig. Gen. Kaleb Luqman, said Houthi forces would adhere to the truce unless there are violations by the coalition.

Six weeks of intense air attacks have failed to significantly loosen the rebels' hold in key areas such as Sanaa.

The U.N. humanitarian coordinator for Yemen, Johannes van der Klaauw, said Sunday that coalition strikes over the weekend had targeted schools and hospitals, in breach of international law.

Houthi fighters claimed Monday that they downed a Moroccan F-16 warplane taking part in the Saudi-led airstrikes.

A rebel-run television channel, al-Masirah, said tribesmen loyal to the Houthis shot down the jet in Saada province, near the Saudi border. There was no word on the fate of the pilot.

The rebel claims could not be independently verified, but Moroccan state media reported that the F-16 went missing Sunday.

President Barack Obama is scheduled to meet this week with Saudi Arabia's crown prince, Mohammed bin Nayef, as part of talks with Persian Gulf Arab envoys at Camp David, Md., over issues such as nuclear negotiations with Iran and the Yemen conflict.