SANAA, Yemen (AP) — Fierce clashes in Yemen’s strategic port city of Hodeida between government forces and Houthi rebels continued for the fifth straight day Wednesday, leaving 52 people dead, including civilians, Yemeni officials said.

The fighting has raged in the district of Hays and town of Durayhimi, just south of the strategic Hodeida port, which handles about 70% of Yemen’s commercial and humanitarian imports, the officials said.

The clashes marked the heaviest bout of violence in months between forces of President Abed-Rabu Mansour Hadi’s government and the Iranian-backed Houthis in the contested city, they said.

Around 70 people, including over two dozen civilians, were also wounded, they said.

The officials, who are from both sides, said the Houthi rebels have attempted to break a siege on Durayhimi, laid by government-allied force known as the Giants Bridges for over two years.

The U.N. mission to Yemen on Monday voiced alarm over the recent escalation of violence in Hodeida. It urged the warring sides to “immediately stop the fighting and return to the joint mechanisms established over the last two years so as not to put the population at further risk and jeopardize the delivery of humanitarian assistance.”

In 2018, heavy fighting erupted in Hodeida after government forces backed by the Saudi-led coalition moved in to wrest control of the strategic city from the Houthis.

After month of clashes, the warring sides signed a U.N.-brokered agreement in December that year that included a cease-fire in the port city and an exchange of more than 15,000 prisoners. The deal, seen as an important first step toward ending the conflict, was never fully implemented.

In oil-rich Marib province, officials said Wednesday that government forces reclaimed areas from the Houthis south of the province. The rebels have for months sought to take control of the province to strengthen their position in ongoing U.N.-mediated peace talks. Government forces also managed to push rebels out of areas in neighboring Jawf province, they said.

At least 28 people from both sides were killed and over 47 were wounded in Marib and Jawf in the past 24 hours, they said.

The officials spoke on condition of anonymity because they were not authorized to brief the media.

The Saudi-led coalition launched airstrikes on the Houthi reinforcement in Jawf, leaving several rebels dead and military equipment damaged, according to Abdu Abdullah Magli, a spokesman for the Yemeni Armed Forces.

The conflict in Yemen began with the 2014 takeover of the capital Sanaa by the Iranian-backed Houthis. A Saudi-led coalition allied with the government has been fighting the Houthis since March 2015.

The war in Yemen has spawned the world’s worst humanitarian crisis, leaving millions suffering from food and medical shortages. It has killed over 112,000 people, including fighters and civilians, according to a database project that tracks violence.