An elderly woman carries bottles of water in a child
An elderly woman carries bottles of water in a child stroller down a street in the frontline town of Chasiv Yar in eastern Ukraine AFP

With the war between Israel and Hamas raging, a UN humanitarian official urged the Security Council on Tuesday to "not lose focus" on Ukraine, especially as another brutal winter looms.

"While much international attention is rightly concentrated on the grave events in the Middle East, it is important that we do not lose focus on other crises," said Ramesh Rajasingham, director of coordination for the UN's humanitarian office, OCHA.

Speaking to the UN Security Council, Rajasingham said the humanitarian situation in Ukraine remained dire as the two-year mark of the Russian invasion approaches, especially in the face of "relentless attacks on civilians."

"Significant damage and destruction of critical infrastructure continues to severely impact access of the civilian population to electricity, heating, water and telecommunications," he added.

Some 18 million people -- 40 percent of Ukraine's population -- are in need of some form of humanitarian assistance, Rajasingham said, speaking on behalf of OCHA chief Martin Griffiths.

"The scale of humanitarian needs in Ukraine more than a year and a half into this war is vast," he said, noting a roughly $1.9 billion shortfall in the $3.9 billion requested for humanitarian needs in the country this year.

"As winter approaches and temperatures start to drop below freezing, humanitarian needs will be magnified."

Some 4 million people living in areas under Russian military control -- in the Donetsk, Kherson, Lugansk and Zaporizhzhia oblasts -- are largely cut off from aid, Rajasingham warned.

"We are extremely concerned about the plight of civilians in these territories whom we are unable to reach at any adequate scale," he said.

"As has been stated before, under International humanitarian law, again, all parties must allow and facilitate the rapid and unimpeded passage of humanitarian relief for civilians in need."