President Obama is to attend the funeral on Sunday of the late Polish president Lech Kaczynski and first lady Maria Kaczynska. Other world leaders are also expected to at the funeral in Krakow, including Russian President Dmitry Medvedev, President Sarkozy of France and the German Chancellor Angela Merkel.
A service in Warsaw’s St John’s cathedral has been held to pay tribute to the president and the other victims of the Russian air crash. Many ex-Polish leaders were in the congregation.
A special joint session of parliament saw politicians, their families and religious leaders pack into the chamber to honour the victims.
Bunches of flowers and photos of MPs who died in the crash were placed on their vacant seats.
The date of the next presidential election is to be announced shortly.
At the presidential palace mourners have been continuing to file past the coffins of the president and his wife as they lie in state.
Outside the queue stretched for kilometres right across central Warsaw.