President Aleksander Kwasniewski has paid tribute to those he described as the martyrs of Polish history - thousands of Polish officers massacred by the Soviets some time in 1940.

The speech was the focal point of ceremonies commemorating the 60th anniversary of the Soviet invasion of Poland.

President Kwasniewski's visit to the Russian forest of Katyn near Smolensk where 4,400 officers are buried, took place despite tensions with Moscow.

Remaining silent throughout the solemn ceremony, President Kwasniewski laid a wreath of flowers in Poland's national colours of red and white in tribute to the officers.

Russia rebuked

Only one official representative of Russian President Boris Yeltsin attended the ceremony in Katyn.

Kwasniewski: "No doubt about the nature of the Soviet invasion"

No high-ranking Russian officials have ever joined Polish leaders at Katyn commemorations since 1990 when Moscow admitted responsibility for the massacre.

Polish-Russian relations were strained earlier this week when the Russian Foreign Ministry denied that the Soviet Army invaded Poland in 1939.

Instead, it insisted that Soviet forces merely seized territory as a buffer to forestall an attack by Nazi Germany.