DONETSK, Ukraine — The shattered remains of a tank bearing a tattered Ukrainian flag sat beside the main highway to Mariupol on Monday afternoon, a remnant of what pro-Russian rebel forces said was a failed attempt by Ukrainian forces to push into rebel-held territory a few days after a shelling attack left 30 dead in that port city.
With a cease-fire in shreds, pro-Russian separatist forces mounting regular new attacks and the Ukrainian military struggling to rebound from losses at the Donetsk airport last week, eastern Ukraine is seeing by far the heaviest fighting since August. Thunderous artillery blasts could be heard from several directions Monday in the largely isolated city of Donetsk.
The Ukrainian government declared a state of emergency in the Donetsk and Luhansk regions, the areas controlled by the rebels, and put the entire country on high alert. In Brussels, at the request of the Ukrainian government, the ambassadors from 28 NATO nations were set to meet on Monday to discuss the situation, the first such gathering since August.
Separatist leaders have said they had no choice last week but to end the shaky cease-fire, which had been in effect since September, and begin offensives to push back Ukrainian forces attacking rebel-held cities.
Ukrainian military officials said the rebel attacks followed a prolonged buildup of heavy weaponry and troops from Russia, something the Kremlin vociferously denies. However, Russia’s president, Vladimir V. Putin, had some harsh words for the Ukrainian military, which he derided as a tool of the West.
On a visit to St. Petersburg, Russia, he said that men were fleeing to Russia rather than become cannon fodder in Ukraine’s military. In essence, this is not an army, he said. This is a foreign legion — in this particular case NATO’s foreign legion, which of course does not pursue the objective of serving Ukraine’s national interests.
Ukrainian officials said that seven of their soldiers had been killed and at least two dozen were wounded in Monday’s fighting. There were reports of some deaths and many casualties in rebel-held regions, but officials there offered no estimates. In all, United Nations human rights officials have said, more than 5,000 people have been killed since fighting started in eastern Ukraine early last year.
Also on Monday, the United Nations humanitarian agency said the Ukrainian government had imposed new restrictions last week on aid agencies seeking to deliver assistance to areas controlled by pro-Russian separatists and, as Jeffrey Feltman, the undersecretary general for political affairs, put it: both sides had hindered access.
According to the Office for the Coordination of Humanitarian Affairs, more than 900,000 Ukrainians are displaced from their homes, and another 600,000 have fled to other countries since the conflict began last March.
Residents reached by phone in Dokuchaevsk, a town a few miles south of that shattered tank, said that shelling had hammered the town all night Sunday and much of the day Monday. No shops were open today and no businesses, said an elderly woman who declined to give her name for fear of reprisals, adding that she and most residents were hiding in basements.
North of the Donetsk airport, around the villages of Peski and Avdeyevka, heavy shelling also could be heard much of the day Monday. Rebel forces in the area have vowed to encircle hundreds of Ukrainian troops camped near the crucial railroad town of Debaltseve, and those villages could be crucial in that effort.
The main access routes out of Donetsk — to the south, toward Mariupol, and to the west, toward Kurakhovo — were closed to all traffic for most of Monday because of nearby shelling. This came just a few days after Ukraine instituted the regulations making it more difficult to get in and out of the city and further added to the growing sense of isolation in the rebel enclave.
At least some shells had also fallen inside Donetsk. At the Central Trauma Hospital, doctors said on Monday that a 9-month-old child and her mother were wounded and the grandmother killed when a shell hit their home.
The screaming baby had been taken away to another part of the hospital to be calmed as the mother was wheeled into surgery Monday afternoon, while the grandmother’s body lay beneath a tattered blue blanket just outside in the hallway.