An Iranian cargo ship loaded with aid bound for Yemen has arrived in Djibouti and is anchored offshore, according to a US official.
Iran's semi-official Fars news agency said on Thursday the ship is in Djibouti waters and will dock "within hours".
The diversion of the ship to the small African country where the UN is coordinating the response to Yemen's conflict would defuse a potential crisis with Saudi Arabia, which had warned the ship not to proceed directly to Yemen.
Iran had provided the ship with a naval escort and warned against any interference.
Iran is accused of supporting the Shia fighters in Yemen, known as Houthis, who seized the capital last year, but Iran denies arming them.
Saudi Arabia views the fighters as an Iranian proxy and has led a coalition in air raids against them since March 26, hoping to restore to power Yemen's internationally recognised President Abd-Rabbu Mansour Hadi, who has fled the country.
US officials said the ship had been heading toward Djibouti for much of the day, escorted by a frigate and a logistical ship known as an oiler.
The officials were not authorised to discuss the matter publicly, so they spoke on condition of anonymity.
US officials earlier this week said they believed there was no lethal aid or weapons in the ship.
Saudi-led coalition warplanes carried out fresh raids on rebel positions in southern Yemen on Thursday as pro-government tribesmen advanced on Houthi strongholds in the north, tribal and army sources said.
Coalition warplanes twice bombed a Houthi gathering on a hill overlooking Taez, from which rebels have been attacking residential neighbourhoods of Yemen's third city, a local government official told the AFP news agency.
He said four civilians were killed and six wounded in overnight mortar fire by the rebel forces - Houthis and renegade troops loyal to former president Ali Abdullah Saleh.
The warplanes also struck rebel positions in nearby Daleh, as well launching three dawn raids on Al-Anad air base in the southern province of Lahj, military sources said.
Arms depots of pro-Saleh forces at Dhamar and Baida provinces in central Yemen also came under air attack several times, residents said.
In main southern city Aden, witnesses reported sporadic fighting on the northern outskirts between rebel militia and forces loyal to Hadi.
A rebel leader, Nabil al-Hashidi, was killed late Wednesday when pro-Hadi fighters stormed his hideout in Aden, tribal sources said, accusing him of spying for Iran.
In the rebel-held northern province of Jawf, pro-Hadi tribesmen seized control of Yatamah, a town on the border with Saudi Arabia, tribal sources said.
On the political front, Iran said it backed UN-brokered efforts to relaunch political talks but was opposed to foreign interference in Yemen's conflict.