The U.S.'s latest sanctions will likely not have much of an immediate effect but will impact Russia's economy in the long-term, experts told ABC News.

With new sanctions on additional entities linked to the Russian defense sector -- and by focusing on the long-term capability of Russia’s oil and gas sector -- the U.S. is “continuing to keep tightening the ratchet” on Russia, Emily Kilcrease, a former U.S. trade official, told ABC News.

Extending the strict export controls that the U.S. imposed on Russia to Belarus -- meaning Belarus also won’t be able to import technology like semiconductors with any U.S-developed components -- sends "a very clear signal that any country that supports Russia is going to be subject to really harsh responses,” Kilcrease, a senior fellow with the Center for a New American Security, said.

Going after oligarchs -- whose assets the Justice Department created a task force to seize -- will have a “psychological” effect on the Russian elite, creating a “feeling of being closed out of the developed world,” Eliot Cohen, a former senior State and Defense Department official who is now with the Center for Strategic and International Studies (CSIS), told ABC News.

The U.S. and Europe have yet to block all imports of Russian oil and gas. Energy expert Ben Cahill said Russia’s energy sector is already feeling "de facto sanctions," with companies reluctant to do business there "because of the fear factor."

Fully sanctioning Russia’s oil and gas exports would "be a much, much bigger scale, the price impact would be dramatic, and it would lead to a scramble around the world for alternative supplies," said Cahill, who is also with CSIS.

The world just doesn’t have enough oil and gas to make up the difference, he said.

-ABC News' Ben Gittleson

In a televised address, Ukrainian President Volodymyr Zelenskyy claimed that almost 9,000 Russian soldiers have been killed since the start of the invasion.

He said in the Mykolayiv region in southern Ukraine they've had to use dozens of helicopters to evacuate dead and wounded soldiers.

"Ukraine doesn't want to be covered with Russian corpses,” Zelenskyy said, appealing to the Russian troops. “Tell your commanders that you don't want to die, get back to where you've come from.”

Ukraine's figures stand in stark contrast to Russian reports on its casualties. Russia's Defense Ministry said earlier Wednesday that 498 Russian service members have been killed and 1,597 wounded since the invasion started.

ABC News hasn't independently verified a total.

-ABC News' Patrick Reevell

Several hundred Stinger anti-aircraft missiles were delivered to Ukraine's military Tuesday, a senior U.S. official has confirmed to ABC News.

Additional shipments of the portable surface-to-air missiles are anticipated in the near future, the official said.

The missiles are part of a $350 million lethal defensive aid package to Ukraine that President Joe Biden authorized late last week. It also includes anti-tank weapons, small arms and body armor.

Germany also announced in recent days it will provide 500 Stinger missiles to Ukraine, along with 1,000 anti-tank weapons.

-ABC News' Luis Martinez

The Society for Worldwide Interbank Financial Communication, aka SWIFT, confirmed Wednesday that seven Russian banks will be removed from its network as part of sanctions issued against Russia over its invasion of Ukraine.

That includes the banks' Russia-based subsidiaries, SWIFT said.

"Diplomatic decisions taken by the European Union, in consultation with the United Kingdom, Canada and the United States, bring SWIFT into efforts to end this crisis by requiring us to disconnect select Russian banks from our financial messaging services," SWIFT said in a statement. "As previously stated, we will fully comply with applicable sanctions laws."

The European Union identified the affected banks as Bank Otkritie, Novikombank, Promsvyazbank, Bank Rossiya, Sovcombank, VEB and VTB.

The sanctions go into effect on March 12, SWIFT said.

-ABC News' Christine Theodorou

The United Nations High Commissioner for Human Rights has "received credible reports of several cases of Russian forces using cluster munitions, including in populated areas," spokesperson Elizabeth Throssell said Friday.

"Due to their wide-area effects, the use of cluster munitions in populated areas is incompatible with international humanitarian law principles," Throssell said.

Throssell added, "We remind Russian authorities that directing attacks against civilians and civilian objects as well as so-called bombardment in towns and villages and other forms of indiscriminate attacks are prohibited under international law and may amount to war crimes."

To date, there have been 26 attacks on health care facilities in Ukraine, killing at least 12 people and injuring 34 people, according to Jašarević. Two of those killed and eight of the injured were healthcare workers.

That number is "shocking," said Throssell.

Throssell and WHO spokesperson Tarik Jašarević declined to pin the blame for all of them on Russia.

This number of attacks includes Wednesday's strike on a children's hospital and maternity ward in Mariupol. On Thursday, Russian officials claimed that the attack was staged, but they first confirmed they bombed it and claimed the hospital was being used by Ukrainian "radicals."

Throssell told reporters that is not true; "It was a functioning hospital," she said.

-ABC News' Conor Finnegan