UN: More than 300,000 driven from homes in Yemen's conflict

More than 300,000 Yemenis have been driven from their homes by a month of violence in the impoverished Arab nation, double the number only two weeks ago, amid escalating fighting with Shiite rebels and the continued Saudi-led air campaign, a United Nations agency said Tuesday.

The report by the Office for the Coordination of Humanitarian Affairs came as warplanes from the Saudi-led coalition throughout the day Tuesday pounded positions of the Shiite rebels, known as Houthis, and allied troops loyal to ousted leader Ali Abdullah Saleh in the capital, Sanaa, and in the south.

The three cities of Dhale, Aden and Taiz --the third largest city in Yemen -- have been declared "disaster zones" by the internationally-recognized government in exile, which said the humanitarian situation is on verge of collapse.

Since March 26, a U.S.-backed alliance of Saudi Arabia and Arab countries has been carrying out airstrikes against the Houthis and Saleh's forces, trying to stop their advance south after they captured Sanaa and much of the country's north last year. The Saudi- and Western-backed president, Abed Rabbo Mansour Hadi, was forced to flee abroad by the Houthi advance and is currently in the Saudi capital, Riyadh.

But so far, the air campaign has been unable to halt the Iranian-allied rebels.

In the early morning hours, multiple explosions shook Sanaa as warplanes struck several rebel-held army camps, trucks carrying weapons and houses turned into weapons' depots for the Houthis, according to residents and officials.

Around midday, airstrikes hit the Sanaa airport to prevent an Iranian plane from landing, security officials in Sanaa said, speaking on condition of anonymity because they were not authorized to talk to the press. Iranian state TV said the plane was carrying medical supplies and made its way back to Iran after being unable to land.

The U.S. and Saudi Arabia and their allies accuse Iran of arming the Houthis, a claim that Tehran and the rebels deny, though the Iranian government says it gives the rebels humanitarian and political backing.

Heavy smoke blanketed Sanaa, said the residents, speaking on condition of anonymity because they feared for their own safety. In Sanaa's northern district of al-Nahda, several strikes hit large caches of weapons stored inside the villas of two top Shiite rebel leaders, officials said.

Other airstrikes hit in the southern port city of Aden, scene of weeks of fierce fighting as Houthis and pro-Saleh troops try to wrest the city from local militias and Hadi loyalists. Strikes Tuesday hit a police commando camp run by pro-Saleh commanders.

OCHA said in a statement Tuesday that because of the "escalating conflict" in 19 provinces, the number of Yemenis displaced from their homes has more than doubled since the 150,000 figure recorded on April 17. It said the highest numbers of displaced were in Hajjah province in the north and two southern provinces, Dhale and Abyan.

Militiamen battling rebels around Aden and Dhale have said that they are running out of ammunition, and a senior official in Hadi's office said Saudi Arabia is trying to find ways to arm them after halting previous method of airdrops of weapons. The airdrops came under criticism because some of the weapons ended up in the hands of Al Qaeda fighters and other Islamic militants. The official spoke on condition of anonymity because he was not authorized to talk to the press.

Meanwhile, a Saudi soldier was killed and another wounded in a gunfight with the Houthis along the kingdom's southern border with Yemen, according to a Saudi security official.  No further details were given about where or when the fighting took place. At least seven other Saudi soldiers have been killed in separate clashes this month along the Saudi-Yemen border.

All officials spoke on condition of anonymity because they were not authorized to speak to the media.