Hungry for defense deals, France has cosied up to the Gulf monarchies, winning several billion-euro contracts in the process, but its strategy of backing one side in the region's Sunni-Shia power struggle is risky, say experts.

These are boom times for France's defense industry, with the country signing 15 billion euros ($16.7 billion) worth of weapons deals this year -- almost double its 8.1-billion tally for the whole of 2014. 

Iran's supreme leader Ayatollah Ali Khamenei on Wednesday accused the United States of supporting "immense crimes" in Yemen by Saudi Arabia, which is leading an air war against Tehran-backed rebels.

"The Saudi government is killing innocent people, women and children in Yemen ... and Americans support these immense crimes," Khamenei said in a speech to students quoted on his official website.

Saudi Arabia on Wednesday beheaded one of its nationals convicted of drug trafficking, bringing to 79 the number of executions this year.

According to AFP tallies, that figure compares with 87 for all of last year and adds to what Amnesty International has called a "macabre spike" in the kingdom's executions of locals and foreigners.

U.S. Secretary of State John Kerry said Wednesday he will discuss with Saudi Arabia the implementation of a "humanitarian pause" in military operations in Yemen in order to help aid operations.

The possibility of a halt in the US-backed Saudi-led coalition raids in the country comes after United Nations warnings that key infrastructure in Yemen -- including water supplies and hospitals -- is on the brink of collapse and that an arms embargo was hampering the delivery of aid.

A husband and wife were killed as a missile struck a Saudi border region across from war-torn Yemen, official media said on Wednesday.

They died on Tuesday when a missile hit their building in the Jazan region, civil defense Major Yahya al-Qahtani was quoted as saying by the official Saudi Press Agency.

Yemen's exiled president wants talks between his country's rival political forces to begin in the Saudi capital on May 17, Qatar's foreign minister said after a regional summit on Tuesday.

This is the first time a date has been mentioned for the proposed talks, which the six-nation Gulf Cooperation Council insists must be held in Riyadh, which is leading a coalition launching air strikes on Iran-backed Yemen rebels.

Saudi Arabia's King Salman said Tuesday that Gulf leaders must stand up to Iran, as Yemeni rebels backed by Tehran attacked a Saudi border town with mortar shells.

Salman's call came at a meeting of Gulf monarchs in Riyadh that was also attended by French President Francois Hollande, who said his country was "by the side" of Gulf nations.

French President Francois Hollande called on Tuesday for abolition of the death penalty, speaking in Saudi Arabia which this year has seen a large rise in the number of executions.

The ultra-conservative Gulf kingdom has executed 78 locals and foreigners, compared with 87 during all of 2014, according to an AFP count.

Mortar shells fired by Iran-backed rebels in Yemen struck the Saudi border town of Najran on Tuesday, prompting a Saudi-led military coalition to warn it would hit back.

The al-Ekhbariya state television showed images of parked cars with windows blown out, chunks torn out of the sidewalk, a building peppered with shrapnel, and one room completely charred and with a hole in the roof. 

France and Saudi Arabia are discussing economic projects worth tens of billions of euros, French Foreign Minister Laurent Fabius said Tuesday.

"If concluded, these 20 projects would be worth tens of billions of euros," Fabius told reporters in Riyadh.