WATCH: 'I call on you to do more,' Zelenskyy tells U.S. lawmakers

Ukrainian President Volodymyr Zelenskyy delivered a virtual address to Congress Wednesday morning. His remarks come as the Russian invasion of Ukraine enters its third week.

Addressing members of Congress via video link, Ukrainian President Zelenskyy issued an emotional plea for increased defense support to Ukraine.

"This is a terror that Europe has not seen, has not seen for 80 years and we are asking for a reply for an answer, to this terror from the whole world," he said Wednesday through a translator.

Speaking remotely to a packed auditorium of House and Senate members, Zelenskyy thanked President Biden for the relief aid the U.S. has already provided but went on to demand more military assistance for Ukraine and economic sanctions against Russia.

"I call on you to do more, new packages of sanctions are needed constantly every week until the Russian military machine stops," Zelenskyy said.

Zelenskyy also called for the U.S. to impose a no-fly zone over Ukraine, a request the White House has already rejected for fear it would escalate international tension with Russia. In pleading for the no-fly zone, he played a produced video showing dramatic footage of the war’s human toll. The video ended with the words: "close the sky over Ukraine."

Calling the invasion the worst war since World War Two, Zelenskyy found similarities between what his country has endured since the Russian military rolled into Ukraine last month and Pearl Harbor and Sept. 11.

And harkening to Martin Luther King’s famous “I have a dream” speech,” Zelenskyy said, “I have a need. I need to protect our sky.”

Before the speech began, Zelenskyy was met with a round of applause from a packed room of U.S. lawmakers. He was introduced by House Speaker Nancy Pelosi.

"Slava Ukraini," Pelosi said, which means "glory to Ukraine." She then prompted the packed room of lawmakers to repeat the phrase.

Lawmakers from both parties have pushed to help Ukraine fight off the Russian military.

Most recently, the Senate passed a resolution on Tuesday night condemning Russian President Putin for committing atrocities and alleged war crimes against the people of Ukraine. Just days ago, Congress approved $14 billion in military and humanitarian aid to Ukraine and is working on legislation to end normal trade relations with Russia.

Zelenskyy has been directly appealing to lawmakers around the world for help in stopping the Russian invasion of his country, which started less than a month ago. He spoke to members of Congress over Zoom on March 5, and this month he has also addressed the European, British and Canadian parliaments.

Biden is expected to speak later on Wednesday about providing more aid to Ukraine.