Aid agencies have begun delivering help to civilians in Yemen as a five-day ceasefire took hold after nearly seven weeks of Arab coalition air strikes against Iran-allied Houthi fighters.
The humanitarian pause - which began at 11pm local time (20:00 GMT) on Tuesday - is the first break in the air war in support of exiled President Abd-Rabbu Mansour Hadi since its launch on March 26 and has strong backing from Washington.
Hours after it took effect a Saudi defence ministry official said rockets were fired from Yemen's Houthi-held north, hitting the border areas of Jazan and Najran inside the kingdom.
The official said there were no casualties and that Saudi forces had "practised self-restraint as part of their commitment" to the truce.
The alleged attack came despite a promise by the Houthis and their allies to abide by the ceasefire.
The Arab coalition has warned it will punish any attempt to exploit the truce.
A US State Department spokesperson said that while the truce was "broadly" holding, it had received some reports of clashes after the ceasefire began.
"We urge all parties to continue to ... honour the commitment to restraint," Jeff Rathke, spokesperson, said.
As aid agencies said they were starting to deliver assistance, residents of the Houthi-held capital Sanaa told AFP news agency the ceasefire came as a much-needed relief.
More than 1,500 people have been killed since mid-March in the air campaign and fighting between the Houthis and Hadi loyalists, according to the UN.
The Houthi fighters, allied with army units loyal to Ali Abdullah Saleh, the former president, have taken control of large parts of Yemen, including Sanaa, and were advancing on Hadi's southern stronghold of Aden when the Arab coalition launched the air campaign.
The weeks since the start of the air war have seen repeated warnings of a dire humanitarian crisis, with shortages of food, water, fuel and medical aid.
The UN's food agency said on Wednesday that the situation in Yemen had become "catastrophic".
Dominique Burgeon, emergencies director at the Rome-based Food and Agriculture Organisation (FAO), told AFP the problems civilians faced were "very serious and at the moment the country lacks everything".
UN agencies and private aid groups had been preparing to boost their efforts since the ceasefire was announced last week and on Wednesday began taking steps.
A ship chartered by the UN World Food Programme (WFP), which arrived in Yemen last week, began distributing its shipment of much-needed fuel to areas across the country, an industry official in the port city of Hodeida told AFP.
The country has been suffering from severe fuel shortages - grinding humanitarian operations to a halt - and news of the deliveries prompted motorists to start queueing at petrol stations in Sanaa.
The head of Doctors Without Borders (MSF) in Yemen, Marie-Elisabeth Ingres, told AFP that her group was hoping to "take advantage of the truce that seems to be holding".
A plane carrying medical aid and MSF personnel was expected in Yemen later Wednesday, she said, with a second aircraft set to follow on Thursday.
War of words over ship
Iran has also announced it is sending an aid ship to Yemen, prompting a fresh war of words with the US.
Iranian Brigadier-General Masoud Jazayeri warned the US against stopping the ship, after the US said it was tracking its movements.
Jazayeri said that if Saudi Arabia or the US "continue to create obstacles on Iran's aid delivery, a fire might start that would definitely be out of their control".
It took several hours for the ceasefire to take hold inside Yemen, with residents and loyalists reporting continued skirmishes in the southern provinces of Daleh and Shabwa, as well as in third city Taiz and the eastern oil province of Marib.
But by Wednesday morning residents said the fighting had largely stopped.
|More than 1,500 people have been killed since mid-March in coalition attacks and fighting between the Houthis and Hadi loyalists [AFP]