WASHINGTON, Dec 20 (AFP) - Ukraine's President Volodymyr Zelensky was expected to visit Washington on Wednesday for a possible meeting with Joe Biden and an address to Congress -- his first trip abroad since Russia invaded in February.

That unannounced trip came as Russian President Vladimir Putin planned to meet senior military officials Wednesday to weigh the results so far of Russia's war and set goals for next year after a series of battlefield defeats.

Zelensky's visit provisionally includes a meeting with Biden in the White House for an announcement of a fresh package of military aid for Ukraine, including advanced Patriot batteries to help defend against Russia's brutal missile attacks, US media reported.

The visit remained tentative and subject to security concerns.

House Speaker Nancy Pelosi told members of Congress in a letter that they should be in attendance on Wednesday evening "for a very special focus on democracy."

She would not confirm the visit to reporters late Tuesday, but said a visit by a "total hero" like Zelensky would "bring honor to the Congress of the United States."

In battling Putin, the Ukraine people "are fighting for democracy for all of us," she said.

Zelensky, who has led without rest for 10 months of brutal war with invading Russian forces, has spoken frequently to leaders and supporters around the world, but only by phone and video conference.

His planned trip acknowledges that the United States has been the most important supporter of the war effort, already providing an estimated $50 billion in total aid, including some $20 billion in security assistance.