Russia-Ukraine updates: 2 US veterans who joined Ukrainian forces missing

In his latest national address, Ukrainian President Volodymyr Zelenskyy continued to call on allies for military aid in the fight against Russia in eastern Ukraine, as the situation in Mariupol remains "severe."

"If we had access to all the weapons we need, which our partners have and which are comparable to the weapons used by the Russian Federation, we would have already ended this war," he said. "We would have already restored peace and liberated our territory from the occupiers. Because the superiority of the Ukrainian military in tactics and wisdom is quite obvious."

Zelenskyy addressed Ukraine's partners directly, saying that "every day matters."

"Any delay in helping Ukraine gives the occupiers an opportunity to kill more Ukrainians," he said.

Zelenskyy said Russian fire has "increased significantly" in the direction of Kharkiv and in the Donbas and Dnipropetrovsk regions. The situation in Mariupol in particular is "as severe as possible," he said, while claiming that the Russian Army is blocking efforts to organize humanitarian corridors.

"The occupiers are trying to carry out deportation or even mobilization of the local residents who have fallen into their hands," the president said. "The fate of at least tens of thousands of Mariupol residents who were previously relocated to Russian-controlled territory is unknown."

-ABC News' Alexandra Faul

President Joe Biden, speaking at the New Hampshire Port Authority on Tuesday, sought to distance his administration from the rising prices and inflation U.S. consumers are facing -- once again pointing to the ongoing COVID-19 pandemic and Russian President Vladimir Putin as the main culprits.

"So, let's be absolutely clear about why we have such high prices now, there are two reasons. First was COVID," Biden said. "And the second big reason for the inflation is Vladimir Putin -- not a joke. Putin’s invasion of Ukraine has up driven gas and food prices all over the world."

Biden said the major breadbaskets for wheat in the world are Ukraine and Russia with the United States and Canada right behind.

"What we saw in the most recent inflation data last month, about 70% of the increase in inflation was a consequence of Putin’s price hike because of the impact on gas and energy prices," Biden said.

Biden said he is doing "everything" he can to lower prices and that savings are already starting to come through for consumers.

"I'm doing everything I can to bring down the price to address Putin's price hike. That's why I authorized the release of $1 million barrels per day for the next six months from our strategic petroleum reserve," Biden said.

Biden said he is calling on Congress to pass his "human infrastructure" bill that has long stalled on Capitol Hill over policy disputes and the price tag.

-ABC News' Mariam Khan

White House Press Secretary Jen Psaki told reporters Tuesday the Biden administration is still weighing additional sanctions against Russia that could be announced by the end of this week.

"I think that we're still ... doing considerations and running a process for additional sanctions, but there are some under consideration. Yes," Psaki told reporters aboard Air Force One.

Psaki also provided a readout of President Joe Biden's call with U.S. allies Tuesday morning, saying the video conference was an opportunity for the world leaders to continue discussing their ongoing efforts to support Ukraine as Russia continues to carry out its assault against the country.

"The leaders reiterated their commitment to continue providing security, economic and humanitarian assistance to Ukraine in its time of need," Psaki said.

"The leaders affirmed their solidarity with the Ukrainian people and condemned the humanitarian suffering caused by Russia's unprovoked and unjustified invasion," Psaki added. "They also discussed their respective diplomatic engagements and their coordinated efforts to continue to impose severe economic costs to hold Russia accountable."

Psaki also said that the United States will continue to provide Ukraine with more ammunition, military assistance and money.

-ABC News' Mariam Khan

U.N. Secretary-General Antonio Guterres is calling for a four-day halt in fighting in Ukraine to coincide with Orthodox Easter.

Guterres said Tuesday that he is asking that a cease-fire begin on Thursday as religious observances get underway.

"I urge all parties -- and all champions of peace around the world -- to join my Easter appeal. Save lives. Stop the bloodshed and destruction. Open a window for dialogue and peace," Guterres said in a video he posted on Twitter.

The U.N. chief said Orthodox Easter is coming amid an intensifying Russian offensive in eastern Ukraine, making a “humanitarian pause” in the fighting all the more urgent.

Guterres said the goal is to allow for the evacuation of civilians from “current or expected areas of confrontation” and to get more humanitarian aid into places where it is desperately needed such as Mariupol, Donetsk, Luhansk and Kherson. More than 4 million people in those areas need assistance, Guterres said.

There was no immediate response from Russian and Ukrainian leaders.

-ABC News' Alexandra Faul