There have been monumental efforts, especially by Poland, to get weapons into Ukraine and to the front lines.

But a senior official told ABC News there are indications Russia may attack one of those supply chains in Poland before it gets to Ukraine, potentially using air power.

Russian forces have created heavily fortified areas from which to launch long-range artillery, the official said, meaning they can shell cities from a distance rather than send troops into them. Ukrainian President Volodymyr Zelenskyy has repeatedly requested air power assistance in order to destroy these fortified areas.

Ukrainians have seen success in attacking Russian resupply areas, mostly in the north but also among smaller, moving groups.

-ABC News' Martha Raddatz

Ukrainian President Volodymyr Zelenskyy has filmed himself from the street just outside his office, but for the first time since the invasion began, he posted a video message from inside.

“We’re not scared, because you’re not scared,” he told Ukrainians who have taken up arms and told Russia it is not welcome.

“So, I stay here at Bankova Street,” Zelenskyy said. “I’m not hiding from anyone and not afraid of anyone as long as it takes to win in this war, our truly patriotic war.”

The latest address was filmed as a selfie in which he showed a view of Kyiv on Monday night.

“This is Kyiv at night outside the window. This is our office. Monday night. You know, we’re used to saying Monday is a hard day,” he said. “But the country is at war now, so every day is Monday.”

-ABC News’ Christine Theodorou

Ukraine’s national nuclear regulator told the International Atomic Energy Agency on Monday that a new nuclear research facility producing radioisotopes for medical and industrial applications had been damaged by shelling in the city of Kharkiv on Sunday.

The incident did not cause any increase in radiation levels at the site.

The nuclear material in the facility is always subcritical, the IAEA said, and the inventory of radioactive material is very low, so the damage reported would not have any radiological consequence.

Eight of Ukraine’s 15 reactors are currently operating, the IAEA said, citing Ukraine’s nuclear regulator.

IAEA Director General Grossi noted there have been several episodes compromising safety at Ukraine’s nuclear sites, including a recent fire at the Zaporizhzhya Nuclear Power Plant, where two reactors are still operational.

-ABC News’ Christine Theodorou

Ukraine and Russia’s foreign ministers have agreed to meet on the sidelines of a diplomatic forum in Turkey on Thursday in what will be the highest level direct meeting between the two sides since Russia’s invasion.

The meeting was agreed following a call between Turkish President Recep Tayyip Erdogan and Russian President Vladimir Putin on Sunday.

Russia’s foreign ministry spokesperson Maria Zakharova earlier confirmed the two had agreed to a meeting. Ukraine’s foreign minister Dmytro Kuleba has also confirmed it.

It’s not clear that there is much the two will be able to agree on, but it still signals a readiness by Russia to talk. For now, Russia is continuing to put forward hardline demands that Ukraine guarantee it will never join NATO or the European Union.

-ABC News’ Patrick Reevell

U.S. Secretary of State Antony Blinken crossed the border into Ukraine Saturday after meeting with Ukrainian Foreign Minister Dmytro Kuleba at the Korczowa Border Crossing Point.

"The entire world stand with Ukraine," Blinken said, and Kuleba added that he hopes Ukrainians will see this as a "clear manifestation that we have friends who literally stand by us."

Blinken said the sanctions imposed so far against Russia are "producing very, very concrete results" and that the pressure will "grow" until this "war of choice is brought to an end."

When asked directly about helping Kuleba with more firepower, Blinken said, "the support for Ukraine not only has been unprecedented, not only is going to continue, it's going to increase."

Kuleba said Ukraine "appreciates" sanctions that have been announced in the last week, but that more economic and political pressure and "necessary weapons," would "save many lives in Ukraine... many sufferings will be avoided."

Kuleba also said that they are “satisfied" with already arranged supplies of anti-tank weapons and ammunition, but that “it’s no secret” they still want fighter jets and air defense systems.

He also thanked the U.S. for sending stingers, and said they were used on Saturday.

"Just today we shot down three Russian attack aircrafts, which were bombing our cities with the use of stingers but we need -- so to say -- big air defense systems to ensure the safety of our skies. If we lose the skies, there will be much, much more blood on the ground,"Kuleba said.

In response to questions about NATO’s refusal to impose a no-fly zone over Ukraine, Kuleba said it’s a "sign of weakness," but stayed optimistic that they will change their minds.

"The time will come," he said.

-ABC News' Conor Finnegan and Justin Gomez