ADEN (Reuters) - Pakistan's parliament voted on Friday not to join the Saudi-led military intervention in Yemen, dashing Riyadh's hopes for powerful support from outside of the region in its fight to halt Iranian-allied Houthi rebels.
Saudi Arabia had asked fellow Sunni-majority Pakistan to provide ships, aircraft and troops for the campaign, now in its third week, to stem the influence of Shi'ite Iran in what appears to be proxy war between the Gulf's two dominant powers.
While Saudi Arabia has the support of its Sunni Gulf Arab neighbors, Pakistan's parliament voted against becoming militarily involved.
"(Parliament) desires that Pakistan should maintain neutrality in the Yemen conflict so as to be able to play a proactive diplomatic role to end the crisis," it said.
Saudi Arabia played down the decision, saying it was not yet a final move because "the Pakistani government has not announced an official position up till now," coalition spokesman Brigadier General Ahmed Asseri told reporters on Friday.
"The presence of our Pakistani brothers would be an addition, but the lack of their ground, naval or air deployment will not affect the operations of the coalition," he added.
The Saudi-led alliance began air strikes in Yemen against the Houthis on March 26 after the rebels, who already control the capital, began a rapid advance towards the southern port city of Aden.
Saudi Arabia is concerned that the violence could spill over the border it shares with Yemen, and is also worried about the influence of Shi'ite Iran, which has denied Saudi allegations it has provided direct military support to the Houthis.
Iran's supreme leader Ayatollah Ali Khamenei has called the Saudi's involvement in Yemen "genocide," raising tensions between the regional powers as fighting on the ground in Yemen threatens all-out sectarian war.
A suicide car bomb detonated outside a security building used by Houthi militiamen in central Yemen on Friday, killing at least 20 people, residents and a local official said.
The local branch of the global Sunni militant group Al Qaeda claimed the attack in the city of Bayhan in Shabwa province, which has witnessed heavy fighting between the Shi'ite Houthi fighters and local militiamen who have been supported by days of Saudi-led air strikes.
Residents said dozens were injured in the huge blast, including several civilians, in the first car bombing since fighting in Yemen rapidly escalated last month.
Coalition air strikes hit Yemen for a sixteenth straight day. In Sanaa, they targeted weapons storage sites used by soldiers loyal to former president Ali Abdullah Saleh, a powerful supporter of the Houthis.
The air raids, which hit the Defence Ministry and other facilities, lasted for hours, residents told Reuters. "The sky was lit up," said Fadel Muhammad. "We heard big explosions."
Saleh is still influential in the military, despite giving up power in 2012 after mass protests against his rule, complicating efforts to stabilize the country.
Troops loyal to him are backing Houthi forces fighting his successor President Abd-Rabbu Mansour Hadi, a former general seen by the Houthis as a pawn of Sunni Gulf Arab monarchies and the West. Hadi has fled to Saudi Arabia.
Yemen's 150,000 barrel-per-day Aden refinery has shut as the conflict worsened, industry sources said. The refinery earlier suspended its tender process for importing oil products, due to the crisis and several tankers headed to the country have been diverted away.
Aden residents said electricity and water had been cut off in several districts, rubbish had been left uncollected and hospitals were unable to cope with the number of wounded.
Fishermen from villages around an hour's drive west of the stricken city said dozens of families in the last two days have taken to the Arabian Sea on rented boats to seek safety in Djibouti in East Africa.
"The humanitarian situation in Aden is catastrophic and disastrous, both in terms of the rising number of killed and injured as well as in declining capabilities of medics, along with shortages in water and electricity," local health ministry official Al-Khadr Lawsar said.
"We call on fighters to adhere to international law and respect the work of ambulances and medical staff in the field," he added, citing the fatal shooting of two brothers working for the Red Crescent while evacuating wounded last week.
Aden residents reported heavy explosions from coalition air strikes and naval bombardment on Houthi positions which shook windows throughout the city.
An Indian ship captain working in Aden was killed in shelling on the city’s dockyard overnight, his company announced, and local media reported that Houthi and allied army units had fired mortars into the area.
An air strike hit a local government compound in the northern suburb of Dar Saad and fires in Aden's outskirts sent plumes of smoke into the air.
Two planes carrying emergency medical aid landed in Sanaa on Friday, the first deliveries from international aid groups since the heavy fighting began.
They were brought in by the International Committee of the Red Cross and the United Nations Children's Fund, UNICEF, which had been trying for days to get aid flights into the country.
Additional reporting by Amjad Ali in Islamabad, Ali Abdelaty and Mohammed Ghobari in Cairo and Dominic Evans and Noah Browning in Dubai; Writing by Michael Georgy; Editing by Tom Heneghan