The White House has announced that President Barack Obama will attend Sunday's state funeral for Polish President Lech Kaczynski, killed last week in a plane crash.
Mr. Obama's press secretary says he will travel to Krakow to express the depth of U.S. condolences to an important and trusted ally.
Mr. Obama led a moment of silence for President Kaczynski Tuesday at the start of the second day of the nuclear summit in Washington.
In Warsaw, the Polish parliament held a special session to honor Mr. Kaczynski, his wife Maria, and other high-ranking Polish officials killed in Saturday's crash.
Polish lawmaker Eugenuisz Klopotek told VOA that if anything good came out of the tragedy, it is seeing people and politicians from all walks of life uniting instead of focusing on divisions.
Tuesday's parliamentary observance began just after the flag-draped coffin bearing the body of first lady Maria Kaczynska arrived in the capital to lie in state next to her husband at the presidential palace.
They were among 96 people killed when their plane crashed in heavy fog last Saturday near the Russian city of Smolensk.
Acting President Bronislaw Komorowski says he will announce a date for presidential elections on Wednesday. Polish law requires the vote to take place within 60 days of the announcement.
The Kaczynski entourage was going to Russia for a memorial service for 22,000 Polish military officers and others executed under orders from Soviet dictator Josef Stalin during World War Two.
Others killed in the plane crash include the chief of Poland's armed forces, the director of the central bank, the deputy foreign minister and Ryszard Kaczorowski. He was 90-year-old Polish president-in-exile from World War II until the collapse of communism 50 years later.