CAIRO/ADEN (Reuters) - A five-day truce in Yemen appeared to be broadly holding on Wednesday, despite reports of air strikes overnight by Saudi-led forces and continued military activity by the Iranian-allied Houthi group.
Witnesses in the southwestern city of Abyan said warplanes had hit positions there after the Houthi seized the area following the start late on Tuesday of the ceasefire, which is intended to ward off a humanitarian catastrophe.
Residents of the southern provinces of Shabwa and Lahj, which have witnessed heavy ground clashes between local militiamen and the Houthis, also reported air strikes overnight.
Saudi Arabia and the Houthis traded accusations of ceasefire violations along the mountainous Yemeni-Saudi border, but residents said hostilities appeared to have largely died down.
An alliance of Gulf Arab nations has been bombing Houthi militia and allied army units that control much of Yemen since March 26 in what they say is an attempt to restore exiled President Abd-Rabbu Mansour Hadi.
Saudi Arabia and its Sunni Muslim allies believe the Houthis are a proxy for the influence of their arch-rival, Shi'ite Iran, in a regional power struggle that has helped exacerbate sectarian tensions across the Middle East.
Aid agencies said the five-day break in fighting to allow fuel, medicine, food and aid workers to enter Yemen could be a "lifeline" for civilians trapped in conflict zones.
"There has been no break whatsoever in the fighting until now, and the people of Yemen need a respite," said Sitara Jabeen, spokeswoman for the International Committee of the Red Cross (ICRC) in the Middle East.
However, there was no immediate word of any new supplies reaching the impoverished nation, that has been beset by more than four years of political chaos and violence.
An Iranian-flagged ship that Tehran says is carrying humanitarian supplies for Yemen could reach the port of Hodeida within four to five days, raising the prospect of a possible confrontation between Saudi Arabia and Iran.
Saudi Arabia, seeking to prevent arms from reaching the Houthis, says it will not let any ships pass without authorisation. Iran says it won't let Saudis search the vessel and has said its warships will escort the vessel.
Yemeni Foreign Minister Reyad Yassin Abdulla said in remarks broadcast on Al Jazeera television that Hadi's government had not been approached by Iran to deliver supplies. He said Hadi's administration had authorised the Saudi-led coalition to "deter whoever thinks he can violate (Yemeni decisions)."
In the bulwark of opposition to the Houthis in the southern city of Aden, the scale of over six weeks of near constant clashes and gunfire emerged.
Over 600 people had been killed and 3,000 had been wounded, while 22,000 residents had been displaced since the Houthis first pushed into the city on March 25, local watchdog group, the Aden Centre for Monitoring, said on Wednesday.
The United Nations believes 828 civilians, including 182 children, have been killed across Yemen since March 26.
Aden locals expressed doubts that the ceasefire would last.
"Aden needs a humanitarian truce so badly, given the lack of food, fuel and everything else. But we question the intentions of the Houthis and believe they will take advantage of the truce to take more areas," said Hassan al-Jamal, a resident of Aden.
Residents said heavy clashes between local militiamen and Houthi fighters broke out in the early evening at Ras Amran, a suburb west of Aden.
Saudi state television quoted an official source at the Defence Ministry as saying projectiles had fallen on the Najran and Jizan areas on Wednesday morning and that some sniper fire by the Houthis had been detected. There were no casualties.
"The position adopted by the armed forces was to exercise restraint, abiding by the humanitarian truce approved by the coalition forces," the television quoted the official as saying.
The Houthis al-Masirah television said at least two shells were fired from Saudi territory towards Yemen and some 150 rounds of automatic fire, but made no mention of any casualties.
The Saudi state news agency SPA said King Salman, at a royal court ceremony attended by President Hadi and Yemeni Prime Minister Khaled Bahah, authorised the laying of the foundation stone for a humanitarian relief centre.
The Saudi-owned al-Arabiya channel said the monarch had allocated one billion riyals (168 million pounds) to the Yemen relief work, in additional to a similar amount he had pledged earlier.
Reporting by Mohammed Ghobari; additional reporting by Omar Fahmy in Cairo, Writing by Noah Browning and Sami Aboudi, editing by Crispian Balmer