Russia-Ukraine updates: Putin says war was ‘unleashed’ on Russia

Poland may send Ukraine MiG-29 fighter jets in the next four to six weeks, Prime Minister Mateusz Morawiecki said on Tuesday, according to Reuters.

Poland has previously said it would consider sending the Soviet-designed fighter jets to Ukraine.

When asked during a press briefing Tuesday how long it could take to supply the aircraft, Morawiecki said, "That could happen in the coming 4 to 6 weeks," according to Reuters.

The White House is welcoming reports that Chinese President Xi Jinping plans to soon speak with Ukrainian President Volodymyr Zelenskyy for the first time since Russia’s invasion began, while cautioning that after speaking with Ukrainian counterparts, "they have not yet actually gotten any confirmation that there will be a telephone call or a video conference."

"We hope there will be," national security adviser Jake Sullivan said during a briefing on Air Force One. "That would be a good thing because it would potentially bring more balance and perspective to the way that the new PRC is approaching this, and we hope it will continue to dissuade them from choosing to provide lethal assistance to Russia."

"We have been encouraging President Xi to reach out to President Zelenskyy because we believe that PRC and President Xi himself should hear directly the Ukrainian perspective and not just the Russian perspective on this," Sullivan continued. "So, we have in fact, advocated to Beijing that that connection take place. We've done so publicly and we've done so privately to the PRC."

Sullivan said the U.S. has “not yet seen the transfer of lethal assistance of weapons from China to Russia," after previously warning it was being considered.

"It's something that we're vigilant about and continuing to watch carefully," he added.

-ABC News' Justin Gomez

Russia said Monday it will extend the Black Sea Grain Initiative after it expires on March 18, but only for 60 days. The announcement came after consultations between U.N. representatives in Geneva and Russian Deputy Foreign Minister Sergei Vershinin.

"The Russian side, noting the package nature of the Istanbul agreements proposed by UN Secretary General António Guterres, does not object to another extension of the Black Sea initiative after the expiration of the second term on March 18, but only for 60 days," Vershinin said, according to Russian media reports.

Russia's consultations in Geneva on the grain deal were not easy, Vershinin said. Russia will rely on the effectiveness of the implementation of the agreement on the export of its agricultural products when deciding on a new extension of the grain deal, according to reports.

Ukraine, which is a key world exporter of wheat, barley, sunflower oil and fertilizer, had its shipments blocked in the months following the invasion by Russia, causing a worldwide spike in food prices. The first deal was brokered last July.

Russian forces suffered more than 1,100 dead in less than a week during battles near the eastern Ukrainian city of Bakhmut, the focal point of fighting in eastern Ukraine, President Volodymyr Zelenskyy said on Sunday.

During his nightly address, Zelenskyy described the battles as "Russia's irreversible loss."

Russian forces also sustained about 1,500 "sanitary losses," meaning soldiers were wounded badly enough to keep them out of further action, Zelenskyy said.

Dozens of pieces of enemy equipment were destroyed, as were more than 10 Russian ammunition depots, Zelenskyy said.

-ABC News' Edward Seekers