SANAA-- The Saudi-led coalition forces and allied Yemeni government troops on Saturday launched a major assault against Shiite Houthi rebels near the Red Sea port city of Hodeidah, security sources said.

It is the second attack along Yemen's western coast in less than two weeks, which began at dawn and simultaneously targeted two rebel-held districts.

In al-Durayhemi district, about 24 km south of Hodeidah, the ground troops loyal to exiled Yemeni President Abd-Rabbu Mansour Hadi advanced from the government-controlled southern city of Mokha on al-Taif area in the southern edge of the district.

The troops from Amalikah (Giant) Brigade, backd by heavy missile bombardment from coalition warships, Apache helicopters and warplanes against hideouts of the Iranian-allied Houthi rebels, cordoned off al-Taif.

Residents of Hodeidah said on social media that powerful explosions could be heard close to the southern side of the port city.

A local security official said hundreds of residents are seen fleeing their homes around and in al-Durayhemi, driving cars or motorcycles to the densely populated Hodeidah.

In Bait al-Fakih district, around 40 km south of al-Durayhemi and 60 km south of Hodeidah, forces commanded by a nephew of the slain former President Ali Abdullah Saleh are fighting their way to recapture al-Jah area of the region.

Last December, Houthis killed Saleh in Sanaa after he broke allegiance with them and allied with the coalition.

In late 2014, Houthis seized the capital Sanaa and much of the country's north, including Hodeidah, forcing the internationally recognized government of President Hadi into exile to Saudi Arabia.

The coalition aims to recapture strategic Hodeidah, which is the only route for aid and commercial supplies to the country's north, and force Houthis to surrender.

Last week, battles in the two districts killed at least 78 from both sides, according to local officials.

Humanitarian agencies working in Yemen have been warning against assault on the port city with 600,000 civilians living in and around it.

The fresh military escalation came four days after the UN envoy to Yemen Martin Griffiths left Sanaa after meeting Houthi officials over resumption of peace talks and cease-fire.

The Saudi-led coalition has been fighting Yemen's Houthi movement since March 2015 to restore Hadi to power.

The war has killed more than 10,000 people, mostly civilians, and displaced over 3 million others, according to the UN agencies.