US media reports say Ukrainian President Volodymyr Zelenskyy is preparing to visit Washington this week. It would be his first trip outside Ukraine since the start of the Russian invasion.

The reports say Zelenskyy is set to address Congress.

US House Speaker Nancy Pelosi encouraged lawmakers to be present for a Wednesday night session.

In a letter to her colleagues, she says it will have "a very special focus on Democracy."

Ukraine has received huge military support from Western countries including billions of dollars in assistance from the United States.

Zelenskyy is expected to appeal for more aid from American leaders.