The Polish Aviation Authorities decided Friday to close air space over Poland.

The airports in Cracow (southern Poland) and Rzeszow (south- eastern Poland) remained open, spokesman for the Polish Aviation Authorities Grzegorz Hlebowicz told the PAP news agency.

The air space over Poland was closed on 0800 hrs on Friday morning. It will be closed until further notice, Hlebowicz said.

The decision has been taken due to the dangers posed by clouds of volcanic ash from Iceland.

The volcano began erupting on Wednesday for the second time in a month from below the Eyjafjallajokull glacier, hurling a plume of ash 6 to 11 km into the atmosphere.

Volcanic ash contains tiny particles of glass and pulverised rock that can damage engines and airframes.

Poland has decided to hold memorial and funeral ceremonies in Warsaw and Cracow this weekend for the victims of the air crash near Smolensk, Russia, which claimed the lives President Lech Kaczynski and his wife Maria, together with other 94 poles on board.