A huge blast lights up the night sky in Yemen after a missile factory was reportedly attacked.

ENORMOUS explosions ripped through suburban Yemen overnight as Saudi-led forces continued intensive air strikes to repel a rebel advance on the Gulf state’s capital.

As night fell yesterday, intense explosions could be heard throughout the rebel-held capital Sanaa, where warplanes had carried out strikes since the early morning. Military officials from both sides of the conflict said air strikes were targeting areas east and south of the third largest city of Taiz, as well as its airport, while naval artillery and air strikes hit coastal areas east of Aden.

“It’s like an earthquake,” Sanaa resident Ammar Ahmed said by telephone. “Never in my life have I heard such explosions or heard such raids.”

He said he could hear missiles whistling through the air and see flames rising from a military area in the southern neighbourhood of Faj Attan, where Scud missiles are believed to be stored.

Ahmed Asiri, the coalition spokesman, told reporters in Riyadh that naval forces are blocking the movement of ships to prevent weapons and fighters from entering or leaving Yemen. He said they had not yet intercepted anything.

Saudi-led naval forces imposed a blockade on Yemen’s ports as coalition air strikes on Monday repelled an advance on the southern port city of Aden by Shiite rebels and forces loyal to a former president, in what appeared to be the most intense day of fighting since the air campaign began five days ago. The move to block ports appeared aimed at preventing the rebels, known as Houthis, from rearming, and comes after the coalition achieved full control of the skies and bombed a number of rebel-held airports. The rebels are supported by Iran, but both Iran and the Houthis deny Tehran has armed them.

Any capital other than Sanaa stores it's missiles & explosives next to heavily populated areas? Screw u Yemeni Army. pic.twitter.com/A19Cyi5Pc2 — Ammar Al-Aulaqi (@ammar82) March 30, 2015

The air strikes have targeted at least nine of Yemen’s 21 provinces and have prevented the Houthis from reaching Aden, the former capital of the once-independent south, where President Abed Rabbo Mansour Hadi declared a temporary capital after fleeing rebel-controlled Sanaa.

Hadi, who was a close US ally against a powerful local al-Qaeda affiliate, fled the country last week, but remains Yemen’s internationally recognised leader. The US has provided support to the Saudi-led coalition but is not carrying out direct military action.

ESCALATING CONFLICT

The conflict marks a major escalation in the regional struggle for influence between Saudi Arabia and Iran, which also back rival sides in Syria’s civil war. Arab leaders unveiled plans Sunday to form a joint military intervention force, which could raise tensions further.

Asiri said much of the air strikes on Sunday and Monday focused on slowing the Houthi advance on Aden. He said the Houthis tried to fire ballistic missiles yesterday but that they malfunctioned. Warplanes then struck the force that had tried to launch them, he said, without providing further details.

Imagine one day u open ur window TO THISS!!! Well, this is what happened for most #Yemen-is in #Sanaa pic.twitter.com/A3CtsiEHsO — Nasser Maweri (@NasserMaweri) March 30, 2015

The Houthis’ TV network said the coalition bombed a displaced persons camp in the northern rebel stronghold of Saada, killing 40 people. Doctors Without Borders tweeted that 29 people from a displaced persons camp were dead on arrival at a hospital it supports and that it treated two dozen injured, among them women and children.

However, witnesses told The Associated Press that the camp — used to house people displaced by an earlier conflict that ended five years ago — is now occupied by Houthi forces and that most of those killed were fighters.

When asked about the allegations, Asiri said the Houthi fighters operate among civilians. It was not immediately possible to resolve the conflicting accounts.

HOUTHI OFFENSIEVE

The Houthis and security forces loyal to former President Ali Abdullah Saleh had earlier launched a fresh offensive against Aden, shelling it and battling local militias, but were pushed back by at least two air strikes, security officials said. Saleh stepped down following a 2011 Arab Spring uprising, but has maintained wide influence through loyalists in the security forces.

Yemeni security officials say the combined force of Houthis and Saleh loyalists is positioned about 30 kilometres (19 miles) east of Aden, near the southern city of Zinjibar. The rebels have used artillery to target pro-Hadi militias known as the Popular Committees. Battles are also underway near the airport. Fighting in the area continued late into the night.

"Another horrifying night" acc 2 friends in #Yemen-say this huge explosion due to airstrikes hitting #Sanaa Arms site pic.twitter.com/7WYwQWpzN8 — Mohammed Jamjoom (@MIJamjoom) March 30, 2015

Reached by telephone, Aden resident Shakib Rajah said that the toughest fighting was taking place near the city’s northern Dar Saad neighbourhood, where heavy weapons including tanks were being used.

The account of the fighting was confirmed by four military and security officials, who spoke on condition of anonymity because they were not authorised to brief reporters.

Emboldened by the air strikes, the Popular Committees have largely held their ground in Aden province and still control most of the city.

The death toll from the ground fighting in Aden since Thursday has reached at least 86, with some 600 people wounded, according to Abdel-Nasser al-Wali, head of a local medical centre.

The strikes in Sanaa have targeted militants, jets, air defence systems and Scud missile launch pads that could threaten Saudi Arabia.

CITIES SHUT DOWN

Officials said aircraft struck areas near the presidential palace in Sanaa and several other sites across the city, sending fireballs rising into the sky, shattering windows and shaking houses. The thunder of rockets, artillery and tank rounds echoed through the streets.

The daily air strikes have bred a climate of anxiety and uncertainty in Sanaa. Schools are shuttered, residents are staying indoors, and hundreds have fled to the safety of nearby villages.

In the southern city of Baihan in Shabwa province, air strikes mistakenly struck a gathering of anti-Houthi tribesmen, causing a number of deaths and injuries, a tribal leader said on condition of anonymity, citing security concerns. It was not clear how many were killed.

An even more detailed video of the arms cache explosion in Sanaa; this one goes on for several minutes. https://t.co/oo0vtjbCwL — reported.ly (@reportedly) March 30, 2015

In the western coastal city of Hodeida, medical officials said one person was killed and others wounded when the Houthis dispersed a demonstration denouncing their takeover and demanding the release of detainees.

Fighting meanwhile intensified in the southern city of al-Dhale, where the Houthis and Saleh loyalists have been trying to open up a corridor to Aden. They have met fierce resistance there, and the city is currently split between supporters and opponents of the rebels.

Since the air campaign began, the Houthis have arrested some 140 foreign nationals on suspicion that they are providing the Saudis with intelligence on the locations of army barracks, radars and air defence positions, according to the rebel-controlled Interior Ministry.