WARSAW, POLAND - President Obama will join the leaders of Russia, France and other nations at the state funeral Sunday of Polish President Lech Kaczynski, who was killed last weekend along with his wife and 94 other people when their plane crashed in Russia.

The funeral will be held in Krakow, where a mass will be said Sunday afternoon at St. Mary's Basilica. Krakow Archbishop Stanislaw Dziwisz said the bodies of Kaczynski and his wife, Maria Kaczynska, will then be carried in a procession across Krakow's old town for burial in a crypt at the 1,000-year-old Wawel Cathedral -- the main burial site of Polish monarchs since the 14th century and of more recent heroes.

In Washington, White House press secretary Robert Gibbs said Obama will travel to Krakow "to express the depth of our condolences to an important and trusted ally." Among other leaders expected to attend are Russian President Dmitry Medvedev and French President Nicolas Sarkozy.

In Warsaw on Tuesday, thousands of mourners joined a half-mile-long viewing line at the Presidential Palace to pay their respects to Kaczynski and his wife as their bodies lay in state. Polish TV broadcast live images of mourners walking by the closed caskets, each flanked by a pair of soldiers.

Parliament held an observance in memory of the president and the 18 lawmakers killed in the crash. In the assembly hall, framed portraits of the lawmakers and flowers bedecked their empty seats.

The Tu-154 plane went down Saturday while trying to land in dense fog at Smolensk in western Russia. The plane full of Polish VIPs had been heading to Russia for a memorial in the Katyn forest for thousands of Polish military officers executed by Joseph Stalin's secret police 70 years ago.

Despite the outpouring of grief for the Polish leader, some Poles criticized the decision to bury Kaczynski, whose combative style earned him many opponents, in a place reserved for the most esteemed national figures. Hundreds staged a protest in Krakow carrying banners reading, "Really worthy of kings?" and "Not at Wawel."

The Associated Press and New York Times contributed to this report.