Aden (AFP) - Yemen's government on Thursday accused the UAE of launching air strikes against its troops in the interim capital Aden in support of separatists who say they have regained control of the southern city.
The United Arab Emirates has trained and supported secessionists who seek an independent southern Yemen, despite being a key pillar in a Saudi-led military coalition backing the government against Iran-aligned Huthi rebels.
"The Yemeni government condemns the Emirati air strikes against government forces in the interim capital Aden and in Zinjibar, which resulted in civilian and military casualties," Deputy Foreign Minister Mohammad al-Hadhrami said in a tweet.
He urged Saudi Arabia "to stand by the legitimate government and stop this illegal and unjustified military escalation".
Neither the UAE nor Saudi Arabia have yet responded to the accusations.
The government said on Wednesday it had seized back Aden from separatists who captured the strategic port city on August 10 after a fierce battle that left at least 40 people dead.
Last week, the UAE denied the government's claims it was "fully responsible for the armed rebellion".
Yemeni Information Minister Muammar al-Iryani tweeted on Thursday that the alleged UAE strikes had killed 40 combatants and wounded 70 civilians.
The fighting has opened a new front in a complex war that has already claimed tens of thousands of lives, sparking widespread malnutrition and what the United Nations calls the world's worst humanitarian crisis.
"The situation is very fragile. Families are again trapped in their homes by fighting, unable to secure food and reach medical care," said the UN humanitarian coordinator in Yemen, Lise Grande.
The NGO Save the Children said its staff in Aden described a climate of terror.
"The situation is very tense; people are scared of what will happen next," acting country director Jason Lee said in a statement.
The UN said at least 13 people were reported killed and 70 wounded during clashes this week.
- Separatists regain control -
The deputy foreign minister did not say when the alleged air strikes took place.
But residents in Aden told AFP they heard air raids late Wednesday when forces loyal to Yemeni President Abedrabbo Mansour Hadi entered Aden, which separatists had captured earlier this month.
On Thursday a spokesman for the separatists' Southern Transitional Council (STC) told AFP the UAE-backed Security Belt Forces, which it dominates, were again in full control of Aden.
A government security source confirmed Aden was under the full control of the STC, saying government troops who had entered the city a day earlier had withdrawn to Abyan province.
Sources on both sides said Thursday that clashes had flared in provincial capital Zinjibar, about 100 kilometres (62 miles) from Aden, after government troops withdrew to the area.
The clashes between separatists and government forces -- who for years fought on the same side against the Huthis -- have raised fears that the country could break apart entirely.
The United Nations Security Council on Thursday voiced concern over the clashes, including what it called a "violent attempt to take over state institutions".
In a statement, it urged all parties to "show restraint and to preserve Yemen's territorial integrity".
- 'Invading forces' -
The separatists have brought massive reinforcements from other regions, officials from both sides said.
STC spokesman Haitham Nezar said the Security Belt forces were now setting their sights on the nearby provinces of Abyan and Shabwa, which had been retaken by government troops earlier this week.
"Our plan is to kick out the invading forces from the south," said Nezar, referring to government troops the separatists see as outsiders.
The Yemeni government has also drafted in reinforcements from the north as the two parties appear to be preparing for a major showdown.
That threatens to create divisions between Riyadh and Abu Dhabi, both of which have called for talks and a ceasefire in Aden.
STC vice president Hani bin Breik said that STC forces fighting the Huthis in the north had been sent to the south for a major battle.
"We will not remain in the fronts to liberate the north from the Huthis while the north is invading us," he said.
The STC is fighting to regain the independence of South Yemen, which unified with the north in 1990.
The Saudi-led coalition intervened in the war in 2015 to back up the government after the Huthis swept south from their northern stronghold to seize the capital Sanaa and much of Yemen, the Arab world's poorest nation.