War planes attacked Yemen's capital Sanaa through the night until dawn, residents of the city told Reuters.
"There were planes strikes all through the night and stopped at dawn," said a resident in Sanaa, adding that explosions were heard in an area west of the capital were a government national guard base was located.
There was no detail on whether the planes belonged to the Saudi-led coalition which has launched attacks against Yemen's Shiite Houthi group in support of President Abdrabbuh Mansour Hadi.
Yemen's president Abd-Rabbu Mansour Hadi has left the southern city of Aden under Saudi protection for Egypt, Saudi-owned al Arabiya television said.
He will attend an Arab summit on Saturday. The Dubai-based satellite channel reported: "Hadi leaves Aden to (Egypt's Red Sea resort of) Sharm el-Sheikh under Saudi protection."
Military and security officials in Egypt have said Saudi Arabia and Egypt will lead a ground operation in Yemen against Shiite rebels and their allies after a campaign of airstrikes to weaken them. Three senior officials have told The Associated Press that forces would enter by land from Saudi Arabia and by sea from the Red Sea and Arabian Sea. Other nations will also be involved by Thursday, they said.
The officials would not specify troop numbers or say when the operation would start, only that it would be after airstrikes weaken the rebels and allied forces loyal to former President Ali Abdullah Saleh.
Saudi Arabia has launched air strikes against Houthi fighters in Yemen, the Saudi ambassador in the US has announced.Read the full story ›
The compound of the Yemeni president is being looted as unrest in the country continues.Read the full story ›
A day of bloodshed has seen at least 126 people have been killed in suicide bomb attacks in Yemen. Some 260 people were also injured in the blasts.
The self-styled Islamic State later claimed responsibility - though the White House later cast doubt on that claim.
Four suicide bombers are thought to have taken part, targeting two mosques in the capital, Sanaa.
Warning: ITV News correspondent Emma Murphy's report contains distressing images from the start:
Two suicide bombers have blown themselves up during noon prayers at two mosques in the Yemeni capital Sanaa killing at least 16 people, a medical source has told Reuters.
Britons in Yemen have been advised to leave immediately after the British embassy was closed, following a takeover of the country by Shiite rebels.
The Foreign and Commonwealth Office said today diplomatic staff were being withdrawn from the country's capital Sanaa amid security fears, saying they were at "increased risk". The US State Department also said it had closed its embassy and evacuated staff.
The United States has reduced the level of staffing at its embassy in Yemen, Reuters news agency reports citing a senior US official.
The change follows several days of clashes around the President's residence in Sanaa.
The army and Houthi fighters clashed in Yemen's capital Sanaa today near the Yemeni president's house, a Reuters witness said.
Gunfire was heard across the city and within close proximity to the president's residence. No further details were immediately available.