May 28, 2022 Russia-Ukraine news

Russia is intensifying its offensive in the Luhansk and Donbas regions as heavy shelling continues in the key industrial city of Severodonetsk. Ukrainian President Volodymyr Zelensky says Donbas faces a "very difficult" moment.

Here's the latest on Russia's war in Ukraine:

Russia successfully tested its Zircon hypersonic cruise missile over a distance of 1,000 kilometers (621 miles) on Saturday, its Ministry of Defense reported. 

The missile was fired from the waters of the Barents Sea towards a “target in the White Sea,” a southern inlet on Russia’s northwest coast.

The missile was fired as part of a broader test of new weapons, according to a ministry statement. 

Video of the test shared by the Ministry of Defense showed the Zircon missile being fired at a steep trajectory from Russia’s Admiral Grigorovich-class frigate at sea. 

The Zircon cruise missile is part of a new generation of hypersonic arms systems that Russia has been developing since at least 2018. 

The Ukrainian military has claimed that Russian units have "suffered significant losses in manpower and equipment" since President Vladimir Putin launched his invasion of Ukraine in late February. 

In a show of force, the Kremlin has continued to conduct high-powered weapons tests, including a test of its new Sarmat intercontinental ballistic missile last month. 

Serhiy Hayday, the head of Luhansk regional military administration, said Saturday the key eastern Ukrainian city of Severodonetsk was "not cut off," as Russian troops press a concerted offensive in the Luhansk region. 

Hayday said intense Russian shelling was underway in Severodonetsk, an industrial center which is the last major stronghold of Ukrainian control in the Luhansk region. 

Severodonetsk, added Hayday, "is not cut off but, by and large, trucks will not pass there, only cars. Many cars were shot on the Lysychansk-Bakhmut route. It is dangerous to pass along that route."

Ukrainian forces are fighting to stave off an apparent effort by Russian forces to encircle the defenders of Severodonetsk, with Russian troops advancing in several directions around a pocket of Ukrainian-held territory.

Hayday said Russia had 25 battalion tactical groups in the Luhansk region -- numbering 10,000 soldiers -- and substantial amounts of military hardware. He said Russian commanders had committed a range of forces to the fight, including conscripts from the self-proclaimed separatist Donetsk and Luhansk People's Republics, fighters from Russia loyal to Chechen Republic leader Ramzan Kadyrov and private military companies, or PMCs.

The Russian occupied region of Kherson has closed its borders to surrounding Ukrainian areas, state media RIA-Novosti quoted Kirill Stremousov, deputy head of the Russian-installed administration in Kherson as saying Saturday.

Kherson’s border crossings with the Ukrainian regions of Mykolaiv and Dnipropetrovsk are closed, while travel from Kherson to Crimea or the Russian-controlled areas of Zaporizhzhia remains possible, Stremousov added.

Nearly all of Kherson — located in Southern Ukraine — has been occupied by Russia since the beginning of Russia's invasion of Ukraine in late February.

Some context: Exit points from Kherson have been unofficially blocked off for weeks, according to Ukrainian officials, who allege that anyone wanting to leave the area has been sent to Crimea.

CNN has spoken to dozens of Ukrainian families at length about their difficult journeys in and out of the region.

Efforts by the Russian-installed administration in Kherson to install military bases and advance a referendum to make the region a “Republic” — mirroring other separatists statelets in eastern Ukraine — are ongoing.

Ukraine's President Volodymyr Zelensky said the situation in Donbas is "very difficult" as Russia ramps up firepower and manpower, and makes incremental gains in the southeastern region. But he vowed Donbas would be "Ukrainian again."

Here's the latest on Russia's war in Ukraine:

The US Defense Department awarded a top defense contractor a $624 million contract to replenish Stinger anti-aircraft missiles, one of the key systems the US has provided to Ukraine as Russia's war continues.

The department announced the contract to Raytheon on Friday afternoon, though it was officially awarded on Wednesday. The contract is "for the procurement of Stinger missiles and associated equipment." There is no timeline listed for completion of the work. 

The US has sent more than 1,400 Stinger systems, including missiles and launchers, to Ukraine to help them challenge Russia's attempt to control the skies. Stingers are short-range anti-aircraft missiles with a range of about 3 miles (nearly 5 kilometers).  

Though their range is too short to allow them to target high-flying aircraft, they can effectively shoot down drones and low-flying aircraft and helicopters. The US has little use for Stingers, but they have been in high demand in Ukraine since the beginning of the invasion.

Ukrainian President Volodymyr Zelensky has promised that Donbas will be "Ukrainian again," as Russian forces continue to make incremental gains in the southeastern region. 

Speaking during his nightly address Friday, Zelensky called the current situation in Donbas "very difficult," referencing Russia's ramping up of firepower and manpower in the region. 

The US Defense Department maintained during a press briefing Friday that Russia is continuing to make "incremental gains" in Donbas. 

Ukraine continues to call on international partners, including the United Kingdom, to provide it with multiple launch rocket systems to counter the Russian offensive. 

While acknowledging Ukraine's request, Pentagon press secretary John Kirby stressed during Friday's briefing that “decisions… haven’t been made yet.” 

The US Defense Department said it is “mindful and aware” of Ukraine’s request for multiple-launch rocket systems, but that “decisions … haven’t been made yet.”

“Our goal from the very beginning has been to try to help them in the fight that they’re in today,” said outgoing Pentagon press secretary John Kirby at a briefing with reporters.

“I won't go so far as to say it's too late to provide the Ukrainians with any system or capability that they might need because they are very active in the fight and they have pushed back the Russians up near Kharkiv,” Kirby said.

However, Kirby said the Defense Department is “mindful of the clock” when it comes to Russia’s invasion of Ukraine.

CNN reported Thursday that the Biden administration is preparing to send MLRS systems as part of a larger package of military and security assistance to Ukraine, which could be announced as soon as next week. The MLRS and its lighter-weight version, the HIMARS, can launch as far as 300 kilometers (186 miles), depending on the type of munition.

Ukrainian officials are denying that Severodonetsk in the Luhansk region is surrounded, but have acknowledged that Russian forces hold one part of the city.

"This is a war, a war against a very powerful enemy, and in theory anything is possible," Hayday said when asked about the possibility of Russian troops gaining further ground in the city. "The higher military command sees this situation. But so far I can't say that in a day, two, three they will completely take over the area. No, most likely they won't."

"We have enough strength," he continued, while also cautioning that, "Maybe there will be a command to our troops even to retreat."