World leaders attend Czech hero Havel's funeral

World leaders gathered in Prague on Friday for the funeral of Czech Velvet Revolution hero Vaclav Havel, who died on Sunday at the age of 75.

French President Nicolas Sarkozy, British Prime Minister David Cameron and US Secretary of State Hillary Clinton and her husband, former President Bill Clinton joined leaders from more than a dozen countries in the historic St Vitus' Cathedral.

The republic's 10.5 million population was to observe a minute's silence at noon expected to stop traffic and work in many places. Neighbouring Slovakia has also declared Friday a day of national mourning and the requiem mass in Prague will be celebrated in both Czech and Slovak.

Havel led his nation through the bloodless 1989 Velvet Revolution that toppled Soviet-backed communism in then-Czechoslovakia.

Tens of thousands of Czechs have filed past Havel's coffin to pay their respects at a church building in the city centre, where Havel's body lay in state before being taken by gun carriage in a solemn procession to Prague Castle's Vladislav Hall on Wednesday.

Authorities left the hall open almost until midnight on Thursday as mourners kept pouring in.

Czech President Vaclav Klaus, foreign minister Karel Schwarzenberg and Czech-born former US Secretary of State Madeleine Albright were to speak at the ceremony inside St Vitus', a 14th century cathedral where traditionally Czech kings were crowned.

Large screens have been set up outside the cathedral to cater for the crowds of mourners expected to throng nearby Hradcany Square.

The playwright served as president of Czechoslovakia from 1989 to 1992 and subsequently the Czech Republic from 1993 to 2003 after the former federation split peacefully into two states.

On Friday evening, a rock concert dedicated to the rock-loving Havel will be staged at the Lucerna Palace, a sprawling edifice built at the turn of the last century by Havel's grandfather, a construction magnate.

Havel's body will be cremated after the funeral in accordance with his family's wishes.

Czech daily DNES quoted Havel's secretary Sabina Tancevova as saying his ashes would be entombed after Christmas, possibly on December 27, at a family crypt in a Prague cemetery.

The funeral is taking place in the same building where a Te Deum -- an early Christian hymn of praise -- was sung in Havel's honour after his election in the aftermath of the Velvet Revolution.

St Vitus Cathedral was founded in 1344 by Czech king Charles IV (1316-1378) of the Luxembourg dynasty, who also founded Prague's Charles University.