TAEZ, Yemen/doha - Fierce fighting raged Saturday in south Yemen between Iran-backed rebels and loyalists of exiled President Abedrabbo Mansour Hadi, as pressure mounted for the warring factions to hold political talks. Clashes left at least 90 people dead on Saturday in towns in the south of the impoverished country, strategically located next to oil-rich Saudi Arabia and key shipping routes. Former strongman Ali Abdullah Saleh, who still holds sway over army units allied with the Shiite rebels, late on Friday urged the Huthis to heed UN demands to withdraw from territory they have seized.

The Huthi rebels, who have overrun large parts of the country and forced Hadi to flee overseas, have demanded a complete end to a month of Saudi-led air strikes against them as a condition for UN-sponsored talks. US Secretary of State John Kerry also called on the anti-government forces to enter into political dialogue to end a conflict that the UN says has killed more than 1,000 people since late March. ‘This has to be a two-way street,’ Kerry told reporters, adding: ‘We need the Huthi and we need those that can influence them to make sure that they are prepared to try to move... to the negotiating table.’ UN Secretary General Ban Ki-moon has announced plans to appoint Mauritanian diplomat Ismail Ould Cheikh Ahmed as his new envoy to Yemen.

Former president Ali Abdullah Saleh called on Friday on all Yemenis to return to political dialogue to find a way to end the country’s spiraling conflict.

Saleh’s loyalists have been fighting alongside Iranian-allied Houthi rebels who toppled the central government, and U.S. Secretary of State John Kerry put the onus for peacemaking on the Houthis and their supporters to cease fire. Saleh also called for talks between Yemenis and Saudi Arabia, which has led a nearly month-long bombing campaign against the Shi’ite Muslim Houthi militia, to be held under United Nations auspices in Geneva.

Saudi-led coalition warplanes continue to target the positions of the Houthis and Saleh loyalists despite announcing an end to the campaign it began a month ago with the goal of helping restore President Abd-Rabbu Mansour Hadi. “I call on all conflicting parties in all provinces to stop fighting and return to dialogue in all provinces,” Saleh, who was forced from power by months of mass protests in 2011, said in an emailed statement.

He also urged the Houthis to accept an April 13 U.N. Security Council resolution calling on them to drop their weapons and quit cities they have seized, after Saudi-led forces stop their intervention in Yemen. Saudi Arabia, the world’s top oil exporter and arch regional adversary of Iran, is concerned about possible security threats posed by the Houthis’ advance across Yemen since last September. Sporadic clashes were reported in Aden on Saturday, after a night of heavy air strikes by Saudi-led forces on Houthi targets in the Lahj provincial capital, al-Houta.

Mohammed al-Bukhaiti of the decision-making politburo of the Houthis’ Ansarullah group said the resolution was impractical and biased. “It is not possible to implement it (the resolution) in practice, especially the issue of disarmament and withdrawal from the cities,” Bukhaiti told Reuters by telephone. The Houthis have argued that laying down their arms and vacating the cities under their control would pave the way for al Qaeda militants to fill the vacuum. Kerry said the Houthis needed to stop fighting and this could bring an end to Saudi air strikes and an opening for a political dialogue.

“This has to be a two-way street,” Kerry told a news conference in Iqaluit, Canada, where he attended an Arctic meeting. “We need the Houthis, and we need those who can influence them, to make sure that they’re prepared to try to move as they said they are to the negotiating table.” Saleh said he was ready to reconcile with all parties that have opposed him since 2011 “for the interest of the nation”.

He further called on all militants, al Qaeda and armed supporters of Hadi to withdraw from the southern port of Aden and hand over power to the army and local authorities.

In Washington, a Pentagon spokesman said a flotilla of nine Iranian naval and cargo ships that U.S. officials feared was carrying arms to Yemen sailed northeast in the direction of Iran on Friday and this should ease U.S. concerns. The Iranian state news agency IRNA, however, quoted Iran’s top navy commander, Admiral Habibollah Sayyari as saying on Saturday that the flotilla was still carrying out its mission in the Gulf of Aden. The Houthis’ Bukhaiti also denied reports that Yemen’s defence minister, General Mahmoud al-Subaihi, and Hadi’s brother Nasser, who led local militias in Aden, had been freed by the Houthis. He said both men were being held as prisoners of war and would eventually be freed when fighting ends.

The appointment becomes official on Monday if no objections are raised by the 15-member council. The fighting has raised fears that Yemen could become a new front in a proxy war between Sunni-ruled Gulf monarchies and Shiite Iran. Tehran rejects accusations it armed the rebels and has presented a peace plan to the UN calling for a ceasefire and the formation of a unity government. A US aircraft carrier headed to Yemeni waters earlier this week to monitor an Iranian convoy that had raised suspicions but redeployed on Friday after the convoy turned back, Pentagon officials said.

At least seven Hadi loyalists and 22 Huthis were killed in dawn fighting Saturday in the town of Daleh, north of key southern city Aden, an official said. Farther east, in Loder, loyalist militiamen killed nine rebels in a rocket-propelled grenade attack, a government official in the town said. There were also heavy clashes in Aden and in third city Taez.

The coalition has kept up air strikes days after announcing its campaign was entering a new phase aimed at resuming the political process, delivering aid and fighting ‘terrorism’. Targets included the rebel-held presidential palace in Aden, which was Hadi's last refuge before he fled to neighbouring Saudi Arabia last month, military officials said. Coalition warplanes also bombed the rebel-held Al-Anad air base north of Aden, which housed US troops supporting a long-running drone war against Al-Qaeda before the fighting forced their withdrawal.

Witnesses reported an air raid targeting a rebel position in eastern Taez. There was also fighting late on Friday in the eastern province of Marib, home to some of Yemen's most important oil fields, army officers and witnesses said. Loyalist troops shelled rebel positions in the Sarwah district, where clashes raged around Yemen's main oil export pipeline.

The 435-kilometre (270-mile) line links Marib's Safir oil fields with the Ras Isa terminal on Yemen's Red Sea coast and control of it has been a key goal for the rebels and their allies. The UN says millions have been affected by the conflict and are struggling to access healthcare, water, food and fuel. It estimates that at least 551 of those killed since late March were civilians and included at least 115 children.

Amnesty International called for an urgent investigation into the civilian deaths. ‘Some of the Saudi Arabian-led air strikes appear to have failed to take necessary precautions to minimise harm to civilians and damage to civilian objects,’ said its MENA deputy head, Said Boumedouha.

‘It is crucial that independent and impartial investigations are carried out to ascertain whether violations of international humanitarian law have been committed.’ And Reporters Without Borders (RSF) said it was ‘extremely worried by the decline in the political and security situation in Yemen’ with attacks from both sides of the conflict at media personnel. Four employees working for Saleh's Yemen Today television, including a presenter, were killed in Monday coalition raids on Sanaa, it said.