Saudi-led coalition warplanes struck government buildings controlled by Houthi fighters in the Yemeni capital Sanaa on Friday night and army units loyal to former president Ali Abdullah Saleh after at least 50 coalition soliders were killed on Friday.
Emirati officials vowed that the deaths in a missile attack in the battleground eastern oil province of Marib would not sap their commitment to the coalition's mission to restore exiled President Abedrabbo Mansour Hadi.
The missile hit an arms depot, triggering huge explosions that the exiled government said also killed five Bahraini coalition troops.
The UAE denounced the attack as "cowardly" but the Shiite Huthi rebels hailed it as "revenge" for six months of deadly coalition air strikes.
The coalition launched its air war when Hadi fled to Saudi Arabia in March after the rebels entered his last refuge, Yemen's second city Aden.
After his loyalists recaptured the southern port city in July, the coalition launched a ground operation which has seen the rebels pushed back from five southern provinces, although they still control the capital Sanaa and much of the north and centre.
UAE troops have played a leading role in the operation and seven had already been killed in the fighting.
But Friday's losses were the heaviest since the formation of the United Arab Emirates in 1971 and, as the bodies of the dead were flown home on Saturday, the country began three days of national mourning.
UAE warplanes retaliated with pre-dawn bombing raids against the rebels in Marib and Sanaa as well as their stronghold of Saada in the far north and the central city of Ibb, state media reported.
Coalition aircraft unleashed waves of air strikes on the rebel-held capital from the early hours, sowing panic among residents.
"These are the heaviest air strikes that Sanaa has endured," a local official told AFP.
The streets remained deserted as the bombing continued into the daylight hours.
Coalition warplanes also bombed the rebel position from which the missile is believed to have been fired, a local official and witnesses said.
The Baihan district of Shabwa province, which borders Marib, is one of the rebels' last redoubts in the south.
In the UAE capital Abu Dhabi, an honour guard stood by as pallbearers carried the coffins of the dead soldiers off a military aircraft at Al-Bateen airport.
"A cowardly attack will not deter us, nor will it stop us from realising our goals," vowed Minister of State for Foreign Affairs Anwar Gargash.
Abu Dhabi Crown Prince Sheikh Mohammed bin Zayed al-Nahyan, head of the Emirati armed forces, vowed that "these events will only make us more steadfast in our stand for justice".
The Huthis said they had fired a Tochka missile at the Safer camp in Marib.
They hailed the strike as "revenge for the crimes and the war of extermination being carried out by the Saudi aggressor and its mercenaries".
The province is the location of Yemen's main oil fields and has seen fierce fighting in recent weeks as loyalist forces and their coalition allies have advanced north.
Loyalist military sources said that the coalition had sent reinforcements to the Safer base this week, including tanks, armoured vehicles, troop carriers, rocket launchers and Apache helicopters.
The extra hardware and troops were intended to boost "the counter-offensive launched by loyalist forces and the coalition to advance on Sanaa", one military official said.
White House Talks
Friday's coalition losses came as Saudi King Salman held talks with US President Barack Obama in Washington at which Yemen figured high on the agenda.
Obama said the two sides "share concerns" about the need to restore a functioning government in Yemen and relieve the humanitarian crisis gripping the country.
More than 4,500 people have been killed in the conflict, including hundreds of children, according to the United Nations, which has warned that the impoverished country is on the brink of famine.
The United States has supported the coalition effort, but repeatedly warned about the impact of the fighting on civilians.
Secretary of State John Kerry telephoned his UAE counterpart Sheikh Abdullah bin Zayed al-Nahyan to express his condolences.
"The United States remains historic friends and strategic partners with both the United Arab Emirates and Bahrain," he said.
"We stand with their citizens during this period of mourning."