UNITED NATIONS, April 17 (Xinhua) -- UN Undersecretary-General for Humanitarian Affairs Mark Lowcock on Tuesday expressed concern about insufficient commercial imports, particularly food, to Yemen.

"We remain very concerned about commercial imports through all of Yemen's ports, most particularly (the Red Sea ports of) Hudaydah and Saleef," Lowcock told the Security Council.

Before the war, Yemen relied on imports to cover 90 percent of staple food and nearly all its medicine and fuel needs, he said. "Commercial shortages and delays at ports have led to sharp increase in the price of food and household necessities. Ports are the lifeline of Yemen."

Price increases, especially of food, are forcing hundreds of thousands of destitute families to turn to humanitarian assistance for their very survival, he said.

The United Nations is encouraging all those concerned to accelerate the normalization of commercial shipments into Hudaydah and Saleef, as well as to Yemen's other ports, he said. "We are worried that shipping companies are reluctant to enter Yemeni waters."

The reasons are related to problems with foreign exchange and the banking sector as well as the ports, but the result is that insufficient food is being imported, he explained.

Lowcock also voiced concern over the fact that Sanaa airport remains closed to commercial traffic. The closure of the airport is preventing thousands of critically ill patients from traveling abroad to seek treatment unavailable in Yemen, he said. Military activities conducted in the proximity of the airport over the last month have affected humanitarian flights as well.

Bureaucratic impediments imposed by decision-makers in Sanaa are affecting relief operations, he noted.

Humanitarian staff continue to face delays in visas and project approvals, restrictions on imports and custom clearance, and long delays and searches at checkpoints, he said.

While UN humanitarian workers have partial access to all of Yemen's 333 districts, restrictions and insecurity mean that estimated 1.2 million people in need of assistance live in areas inaccessible to humanitarian organizations, he noted.

As with other challenges, a successful response requires safe, unimpeded and unhindered access across and into Yemen for humanitarian staff and humanitarian supplies, he said. "All impediments which prevent humanitarians from reaching people must stop."

Yemeni public servants who are doing so much themselves to respond to the crisis need their salaries paid, said Lowcock, noting that most health and sanitation workers have still not been paid for more than a year and a half.

Lowcock expressed concern over the security situation in the country.

The impact of airstrikes, shelling and fighting on the civilian population is deeply worrying, said Lowcock. "Civilian lives are lost. Public infrastructure is destroyed. Displacement is increasing."

Mines and the remnants of war affect agricultural production and the wider economy, and therefore threaten civilian life. Some 3 million women and girls are at risk of sexual and gender-based violence, he said.

He warned of the risk of another major cholera outbreak. Last year's outbreak of cholera and watery diarrhea struck more than 1 million people. With the arrival of the rainy season, the conditions that created this outbreak are still present, he said.

Yemen, which has been in war since 2015, remains the world's worst humanitarian crisis, he said. Three quarters of the population, or more than 22 million people, urgently require some form of humanitarian help, including 8.4 million people who struggle to find their next meal, said Lowcock.

The United Nations increased the coverage of food assistance last year from 3 million people a month in January to more than 7 million a month in December. For 2018, the World Food Programme has plans to reach 10 million people a month, said Lowcock.