Russians control 80% of key Ukraine city, cut escape routes

"There is still an opportunity for the evacuation of the wounded, communication with the Ukrainian military and local residents," he told The Associated Press by telephone, adding that Russian forces have not yet completely blocked off the strategic city.

About 12,000 people remain in Sievierodonetsk, from a pre-war population of 100,000. More than 500 civilians are sheltering in the city's Azot chemical plant, which is being relentlessly pounded by the Russians, according to Haidai.

In all, 70 civilians were evacuated from the Luhansk region in the last day, the governor said.

A Russian general, meanwhile, said a humanitarian corridor will be opened Wednesday to evacuate civilians from the Azot plant. Col-Gen. Mikhail Mizintsev said evacuees would be taken to the town of Svatovo, 60 kilometers (35 miles) to the north in territory under the control of Russian and separatist forces.

He said the plan was made after Ukraine called for an evacuation corridor leading to territory it controls.

Mizintsev, head of the National Defense Management Center, is accused by Ukraine of human rights violations while commanding troops during the long siege of Mariupol, Ukraine's key port on the Sea of Azov that has been taken over by the Russians.

Russian forces in the past few weeks have pressed hard to capture Ukraine's eastern industrial Donbas area, which borders Russia and is made up of the regions of Luhansk and Donetsk.

"The situation is difficult," Ukrainian President Volodymyr Zelenskyy said in a news conference Tuesday with Danish media. "Our task is to fight back."

With the conflict now in its fourth month, the battle of Donbas could dictate the course of the war.

If Russia prevails, Ukraine will lose not only land but perhaps the bulk of its most capable military forces, opening the way for Moscow to grab more territory and dictate its terms to Kyiv.

A Russian failure, however, could lay the grounds for a Ukrainian counteroffensive — and possible political upheaval for the Kremlin.

Jan Egeland, the Secretary-General of the Norwegian Refugee Council, one of the aid organizations supplying food to civilians in the Donbas, said fighting in the past few weeks has made regular food distributions impossible. Now, he said, the remaining civilians in Sievierodonetsk "are almost entirely cut off from aid supplies after the destruction of the last bridge."

Reports of overnight shelling came from other Ukrainian regions as well, with five people wounded in the northeastern Kharkiv region. According to an intelligence update Tuesday by the U.K. Defense Ministry, Russian forces appear to have made small advances in the Kharkiv sector for the first time in several weeks.

A regional Ukrainian military official said the country's air defense shot down two Russian cruise missiles targeting the southern region of Odesa, a key western port on the Black Sea.