A two-minute silence was observed across Poland today to remember those who died in yesterday's plane crash in western Russia.

A Polish military aircraft bearing the coffin of President Lech Kaczynski arrived in Warsaw this afternoon, a day after he and many members of Poland's elite were killed in a plane crash in Russia.

The only child of the late president and his wife, along with acting President Bronislaw Komorowski, Prime Minister Donald Tusk and other officials met the coffin at the military airport after its short flight from Smolensk in western Russia where the crash occurred in thick fog.

After a short religious ceremony at the airport, the coffin was driven under military escort to the presidential palace where it will be available for public viewing.

An investigation into the circumstances of the crash is to be led by Russian Prime Minister Vladimir Putin.

Last night, thousands of people gathered outside the Presidential palace in the Polish capital, Warsaw, as seven days of national mourning were declared.

President Mary McAleese attended a special mass in Dublin this afternoon, which was organised by the Polish community in Ireland.

Earlier, hundreds of members of the Polish community in Northern Ireland attended a special Mass in East Belfast to remember all those who died in the plane crash.

Fr Andrzej Kolaczkowski, chaplain to the Polish community who celebrated the mass at St Anthony's in Willowfield, said the tragedy was hard to come to terms with.

‘The loss of one person has a huge effect but the loss of 97 people who also played an important role in Polish politics and Polish social life is very, very daunting’, he said.

Fr Kolaczkowski read out the names of all those who had died in the crash.

Members of the congregation placed flowers at an altar beside a picture of the President and his wife and draped with the red and white colours of the Polish flag.