Russian forces have attacked Ukrainian communications infrastructure to "reduce Ukrainian citizens' access to reliable news and information," the U.K. Ministry of Defence said on Monday.

"Russia reportedly struck a TV tower in Kharkiv yesterday, suspending broadcasting output," the Ministry’s update said.

Russian forces on March 1 struck a TV tower in Kyiv, the capital.

Russia declared a cease-fire starting Monday morning, opening humanitarian corridors for the evacuation of civilians from Kyiv, Mariupol, Kharkiv and Sumy, the Russian interagency humanitarian response staff in Ukraine said.

"Taking into account the disastrous humanitarian situation and its severe deterioration in the cities of Kyiv, Kharkiv, Sumy, and Mariupol, and also at French President Emmanuel Macron's personal request to Russian President Vladimir Putin, the Russian Armed Forces are declaring a ceasefire and opening humanitarian corridors for reasons of humanity starting 10:00 a.m. on March 7, 2022," the staff said.

Ukrainian officials in Mariupol said Russia broke planned cease-fires on Saturday and Sunday. Russia's announcement on Monday of humanitarian corridors was "unacceptable," a Ukrainian official said, saying all of Russia's planned routes led to Russia.

The Ukrainian armed forces have received approximately 3,000 applications from the U.S. to join the fight against invading Russian troops, a Ukrainian Embassy official confirmed to ABC News.

Voice of America was first to report the news this weekend.

-ABC News’ Conor Finnegan

In a new letter to House Democrats, Speaker Nancy Pelosi reiterated plans to approve new aid for Ukraine in a government funding measure this week.

She also said new legislation to ban the import of Russian oil and energy products would repeal normal trade relations with Russia and Belarus and deny Russia access to the World Trade Organization.

The measure would also give the administration more power to raise tariffs on Russian imports.

Pelosi said Congress and the Biden administration “remain laser-focused on bringing down the higher energy costs for American families and our partners,” noting that 60 million barrels of oil have been released from strategic reserves and allies have said they will reduce their dependence on Russian energy.

“With the West’s carefully coordinated effort to sequence sanctions on Russia and mitigate for the costs of these efforts, we are standing up for our values abroad while protecting our families at home,” Pelosi wrote in the letter.

It’s not clear when the House will take up this measure, but Congress needs to approve government funding -- which will include the Ukraine aid -- by Friday.

-ABC News’ Ben Siegel

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