Poland has begun a week of national mourning over the deaths of president Kaczynski and 96 others on the plane that crashed in Russia. A nationwide two minutes of silence are to be observed at midday. The remains of the president and his wife are due to arrive back in the country later in the day. Condolences have meanwhile been pouring in from around the world. US President Barack Obama said Kaczynski was a distinguished statesman widely admired in the United States. German chancellor Angela Merkel called the Polish president a fighter for his country's interests.