Yemen's rebels fire into Saudi Arabia

Three people were killed in a cross-border mortar bomb and rocket attack by Yemen rebels on a city in southern Saudi Arabia, the interior ministry said.  

It did not specify if those killed were civilians or troops.  

Fighting along the frontier has killed 12 soldiers and border guards but no civilian casualties have so far been reported. 

"Three dead after Najran region attacked by mortar rounds and random Katyusha rockets from Yemen territory," the interior ministry said in a tweet sent late Tuesday.  

Brigadier General Ahmed al-Assiri told state television that rebel fire hit "hospitals, schools and civilian homes" in the city and surroundings.  

He said casualties occurred at a field hospital outside the city.  

Saudi news channel Al-Ekhbariya showed footage of cars with windows blown out, chunks torn from pavements, a building peppered with shrapnel and one completely charred room with a hole in the ceiling. 

Tuesday's assault was the first by the Houthis on an inhabited Saudi town.  

It came as leaders of the six Gulf Cooperation Council states gathered for a special summit in Riyadh, with French President Francois Hollande in attendance.  

The leaders said they welcomed a decision by Yemen's exiled President Abedrabbo Mansour Hadi to host a meeting of Yemeni political forces in Riyadh later this month with a view to resolving his country's crisis.  

But the rebels reject holding talks in the Saudi capital. Iran, which denies accusations of arming the Huthis, has called for negotiations at a neutral location. 

Earlier on Tuesday, the Red Cross and Doctors without Borders (MSF) said that the humanitarian situation in Yemen is "catastrophic" and attacks against civilian infrastructure, such as Sanaa airport, should stop, in a rare joint statement.

Airstrikes by the Saudi-led coalition targeting Sanaa and Hodaida airports are preventing humanitarian assistance from entering the country, in light of the restrictions on importations imposed by the coalition and severe fuel shortages in Yemen.  

Saudi Arabia launched airstrikes on March 26 targeting Houthi movement fighters, as well as allied army units loyal to former president Ali Abdullah Saleh, who are accused of seeking to overthrow the Yemeni state.  

"Yemen depends almost completely on imports of food and medication especially for the treatment of chronic disease," Cedric Schweizer, the head of the Red Cross' staff in Yemen, said.

"Sanaa airport was an essential civilian infrastructure, and the main lifeline to supply essential humanitarian goods and services," Schweizer added. " The harsh restrictions on importations imposed by the Coalition for the past 6 weeks, added to the extreme fuel shortages, have made the daily lives of Yemenis unbearable."

This was echoed by MSF's head of mission in Yemen, Marie Elisabeth Ingres.

"The destruction of Sanaa runway means that countless lives are now more at risk, and we can no longer afford to stand and watch as people are forced to drink unsafe water and children die of preventable causes," Ingres said.

The joint statement comes after repeated warnings regarding the humanitarian situation in Yemen, the poorest country in the Middle East, where 1,200 people have died since March 19, according to the UN.

French aid group Action Against Hunger urged French president Francoise Hollande on Monday to call for a ceasefire during his visit to the Saudi capital Riyadh on Monday, where he is attending an extraordinary meeting of the Gulf Cooperation Council.

Saudi Arabia, which currently hosts the Yemeni president Abd Rabbo Mansour Hadi and a number of other Yemeni political figures, has said that it is considering temporarily halting airstrikes to allow humanitarian aid to get in.

The coalition is to discuss areas inside Yemen where "all air operations will be paused at specific times to allow for the delivery of aid," Saudi foreign minister, Adel al-Jubeir, said on Monday.