According to sources, Ukrainian President Volodymyr Zelensky is scheduled to travel to Washington on Wednesday and may have a meeting with US President Joe Biden.
Since the Russian invasion in February, he had not traveled outside of the country.
Unnamed authorities told US media that Mr. Zelensky could also address Congress. Neither the visit nor the plans have received formal confirmation.
Security concerns would make a visit risky, so last-minute changes to plans were certainly a possibility.
Democratic House Speaker Nancy Pelosi asked members of Congress to attend the event on Wednesday night in a letter on Tuesday.
Mr. Zelensky has visited troops all around Ukraine and frequently receives foreign officials in the country’s capital, Kyiv. On Tuesday, he paid an unexpected visit to the battleground city of Bakhmut.
The president of Ukraine has frequently communicated with foreign leaders via phone and video calls, frequently from his office in Kyiv.
But an unannounced trip abroad would be a first since the war started, and it would also underscore the significance of Ukraine’s relationship with the US, which has been instrumental in providing military support.
Since the beginning of the conflict, the US has invested $18.5 billion (£15.1 billion) in direct military support, significantly more than any other nation (to 20 November).
The monthly cost of defense for Ukraine, according to President Zelensky, is about $5 billion (£4.1 billion). He has pleaded for more funding.
The administration of President Joe Biden is reportedly considering giving Ukraine Patriot missiles so that it can defend its crucial infrastructure from Russian strikes, according to recent reports in US media.
Russia has been attacking Ukraine’s energy industry, leaving millions in the dark during winter months when the temperature is well below zero.
President Zelensky unexpectedly paid a visit to the front-line city of Bakhmut on Tuesday, where Ukrainian and Russian soldiers have been engaged in a bloody, months-long conflict.
According to the president, he visited with soldiers and presented honors to the military.
The visit was a powerful act of resistance and a show of solidarity with Ukrainian forces fighting in some of the bloodiest engagements in recent weeks.
In a moment caught on tape, soldiers handed Mr. Zelensky a Ukrainian flag bearing their signatures and urged him to present it to President Biden and the US Congress.
The office of Mr. Zelensky has not made any public statements regarding a potential trip to the US.