Civilians are reportedly sheltering from Russian shelling under a chemical plant in the Ukrainian city of Sievierodonetsk that authorities fear may still have stocks of dangerous materials.
Russian forces on Wednesday (local time) fought their way into the centre of the industrial city and appeared to be close to claiming a big prize in their offensive in the eastern Donbas region.
However, in a boost for Ukraine, the United States has announced a new, $700 million ($977 million) weapons package for Kyiv that will include advanced rocket systems capable of hitting targets up to 80 km away.
Russian forces entered Sievierodonetsk — the largest city still held by Ukraine in the eastern Luhansk region — on May 27 after weeks of shelling as they try to take full control of the industrial Donbas region.
On Tuesday, Ukraine said a Russian air strike hit a nitric acid tank in Sievierodonetsk, releasing a large pink cloud.
"There are civilians there in bomb shelters, there are quite a few of them," Luhansk regional governor Serhiy Gaidai said of the Azot chemical plant, adding that there were "strong Soviet-era" bomb shelters under the factory.
"We were assured that there were no [chemicals] left, but as we can see there are still some remnants," he said, referring to Tuesday's discharge.
Reuters could not independently confirm the account.
Mr Gaidai said the plant was not likely to become the site of a weeks-long siege similar to the Azovstal steel complex in the south-eastern city of Mariupol.
The Ukrainian military did not put up fortifications in the plant because of the chemical risk, he said.
"We will defend the region to the last city, village or resident of Luhansk region. We will do everything possible, and even the impossible, not to let the enemy advance further," he said.
He said some humanitarian supplies, including water and medicine, had been built up before the Russian attack but that Ukraine had lost contact with the city's hospital.
One bridge into Sievierodonetsk from the neighbouring city of Lysychansk had been destroyed and the other had been damaged but was still passable by light vehicles, Mr Gaidai said.
'The enemy has entered the centre of Sievierodonetsk'
After days of heavy fighting around Sievierodonetsk — much of which has been laid to waste by Russian artillery bombardments — Russian troops were inching forward through the city's streets.
"The enemy has entered the centre of Sievierodonetsk and is trying to take up positions. The situation is very difficult," Ukrainian military spokesman Oleksandr Motuzyanyk told a briefing.
"I do not want to evaluate or give any percentage of what we control and do not control. We know the enemy’s goals and are doing everything to prevent them from being achieved," he said.
If Russia captures the city and its smaller twin Lysychansk on the west bank of the Siverskyi Donets river, it will hold all of Luhansk, one of two provinces in the eastern Donbas region that Moscow claims on behalf of separatists and a key war aim of President Vladimir Putin.
Mr Gaidai said 70 per cent of the city was under Russian control, about 10-15 per cent "a kind of grey zone" and the rest was held by Ukrainian defenders.
"There have been some counter-attacks on separate streets," he said.
Mr Gaidai said Lysychansk was easier to defend because it was located on a hill but that Russian forces would target it with artillery and mortars once in full control of Sievierodonetsk.
The leader of the pro-Moscow Luhansk People's Republic, Leonid Pasechnik, told TASS news agency that Russian proxies had advanced slower than expected to safeguard city infrastructure and "exercise caution around its chemical factories".
Jan Egeland, head of the Norwegian Refugee Council aid agency which had long operated out of Sievierodonetsk, said up to 12,000 civilians remain trapped in the crossfire, without sufficient access to water, food, medicine or electricity.
Before the war, the city was home to around 120,000 people.
New weapons package
The new US weapons package includes M142 High Mobility Artillery Rocket Systems (HIMARS) — which Kyiv has said are "crucial" to counter Russian missile attacks — along with ammunition, counter-fire radars, air-surveillance radars, additional Javelin anti-tank missiles and anti-armour weapons, officials said.
"The United States will stand with our Ukrainian partners and continue to provide Ukraine with weapons and equipment to defend itself," President Joe Biden said in a statement.
The decision to give Ukraine the rocket systems was made after Washington received assurances from Kyiv that it would not use them to hit targets inside Russian territory, which could seriously escalate the war.
Ukraine has been seeking Multiple Rocket Launch Systems (MLRS) — such as the M270 and M142 HIMARS — to provide more firepower at longer range to hit Russian troop concentrations and weapons stockpiles at the Russian forces' rear.
Deputy White House national security adviser Jonathan Finer said Washington believed the system would meet Kyiv's needs.
"This is a defensive conflict that the Ukrainians are waging," Mr Finer said in an interview with CNN.
The new supplies come on top of billions of dollars worth of equipment such as drones and anti-aircraft missiles.
Russia, however, warned of an increased risk of direct confrontation with the United States.
"We believe that the United States is purposefully and diligently adding fuel to the fire," Kremlin spokesman Dmitry Peskov told reporters, adding that such supplies would not encourage Ukraine's leadership to resume stalled peace talks.
Shortly after the US decision to provide the longer-range rockets was announced, the Russian defence ministry said Russia's nuclear forces were holding drills in the Ivanovo province, north-east of Moscow, the Interfax news agency reported.
Some 1,000 servicemen were exercising in intense manoeuvres using more than 100 vehicles including Yars intercontinental ballistic missile launchers, it cited the ministry as saying. The report did not mention the US decision.
ABC/Reuters
