UN staff were evacuated from Yemen's capital Saturday after a third night of Saudi-led air strikes, as President Abedrabbo Mansour Hadi urged his Arab allies to bomb Iranian-backed rebels into submission.
The impoverished and deeply tribal Arabian Peninsula state, on the front line of the US battle against Al-Qaeda, is the scene of the latest emerging proxy struggle between Middle East powers.
A Sunni Arab coalition, led by Saudi Arabia and other Gulf monarchies, is battling to avoid having a pro-Iran regime on its doorstep, as Shiite Huthi rebels tighten the noose around Hadi's southern stronghold Aden.
"I call for this operation to continue until this gang surrenders and withdraws from all locations it has occupied in every province," Hadi told an Arab League summit in the Egyptian resort of Sharm el-Sheikh.
"I say to Iran's puppet and whoever is with him, you are the one who destroyed Yemen with your political immaturity," Hadi said.
Hadi later flew to Saudi Arabia with King Salman and does not plan to return to Yemen until "the situation settles," said Foreign Minister Riyad Yassin.
"The Huthis are trying to take it (Aden) by any means to impose a new reality on the ground before the summit ends," Yassin added.
Heavy coalition strikes shook the rebel-held capital for a third consecutive night until dawn Saturday, residents said.
"It was an intense night of bombing and the windows shook," said a foreigner working for an international aid organisation in Sanaa.
More than 200 staff from the UN, foreign embassies and other organisations were later evacuated by air, aid workers said.
The latest strikes apparently targeted mainly arms depots and other military facilities outside Sanaa, witnesses said.
Saudi Arabia says more than 10 countries have joined the coalition defending Hadi.
The Western-backed leader had gone into hiding earlier in the week as rebel forces bore down on Aden and a warplane attacked the presidential palace there.
He surfaced in Riyadh Thursday before heading to the Egypt summit.
– Arms depot blasts –
At least 61 people have been killed and around 200 wounded in three days of fighting between Shiite rebels and anti-Huthi militia in Aden, the city's health department director Al-Kheder Lassouar said.
Nine charred bodies were pulled from an arms depot in a cave near the port city after a series of massive blasts, with the death toll expected to rise, he said.
The cause was not immediately clear but residents had been looting the arsenal of Soviet-era weapons.
The two-day Arab summit, which opened Saturday, is expected to back the offensive against the rebels and approve the creation of a joint military force to tackle extremists.
Egyptian President Abdel Fattah al-Sisi told fellow leaders the region faced "unprecedented" threats.
And Saudi King Salman vowed that the air strikes would continue until they bring "security" to the Yemeni people.
But UN Secretary General Ban Ki-moon urged Arab leaders to "lay down clear guidelines to peacefully resolve the crisis in Yemen".
– Campaign could last months –
Saudi warships evacuated dozens of foreign diplomats from Aden hours before the kingdom launched the air strikes on the advancing rebels, state television said on Saturday.
Saudi Arabia has vowed to do "whatever it takes" to prevent Hadi's overthrow.
But experts say the Saudis will be reluctant to send in ground troops for fear of getting bogged down in a protracted conflict.
The Huthis are backed by army units loyal to former president Ali Abdullah Saleh, who stepped down in 2012 after a year-long popular uprising and is accused of supporting the rebels.
Saleh issued a call Friday for a ceasefire and the resumption of UN-brokered dialogue between warring parties.
Gulf diplomats said the air strikes could last up to six months and accused Iran of providing "logistical and military support" to the rebels.
"According to estimates, there are 5,000 Iranians, (members of the pro-Tehran Lebanese movement) Hezbollah and Iraqi militia on the ground in Yemen," said one Gulf official, who did not want to be named.
It was not possible to independently verify the claim.
The Gulf officials said Riyadh and its allies had decided to intervene after satellite imagery in late January showed the movement of Scud missiles north towards the Saudi border, with the capacity to strike a large part of the kingdom's territory.
US President Barack Obama spoke to King Salman and said Washington shared a "collective goal" with its regional ally to see stability in Yemen.
Washington has pledged logistical and intelligence support for the Saudi-led campaign.
The US military also rescued two Saudi pilots forced to eject from their fighter jet over the sea off Yemen after a technical problem.