Washington  - Thousands of mourners gathered to pay their last respects to Democratic Party icon Edward Kennedy as his casket was opened for public viewing Thursday at the presidential library in Boston of his brother, John F Kennedy.

Kennedy's family earlier held a private Mass at the senator's home in Hyannis Port, Massachusetts. A hearse and motorcade then made the three-hour journey north to the state capital, Boston, following a route past important sites in the lives of Kennedy and his family.

Among the landmarks was Faneuil Hall, a colonial-era marketplace and meeting hall in the heart of Boston. The city's Mayor Thomas Menino rang its bell 47 times - one ring for every year that Kennedy served in the US Senate.

Known as a "lion" of the Senate and the voice of his left-leaning Democrats in the chamber, Edward "Ted" Kennedy died Tuesday night after a lengthy battle with brain cancer.

Thousands of his supporters gathered along the motorcade route in Hyannis Port and Boston to catch a glimpse of the hearse, carrying the senator's casket and followed by members of the Kennedy family.

Thousands more waited in line to view the casket at the JFK Library and Museum, where it will remain open to the public until Friday afternoon. Uniformed members of each branch of the US military helped carry Kennedy's casket into the building.

Ted Kennedy helped build the library in honour of his brother, who was assassinated as president in 1963.

The family is planning another memorial service Friday night at the library and a funeral mass Saturday morning at Boston's Our Lady of Perpetual Help Basilica. Hundreds of dignitaries and all four living former US presidents were expected to attend the funeral.

President Barack Obama, whose bid for the White House received a big boost from Kennedy's endorsement in early 2008, will deliver the eulogy at the Boston funeral, White House spokesman Bill Burton said.

Vice President Joe Biden and former Republican presidential nominee John McCain, who both spent decades as Kennedy's Senate colleagues, were among those slated to speak at the memorial Friday.

A burial service will be held Saturday afternoon at Arlington Cemetery in Virginia, overlooking Washington. Kennedy will be laid to rest near his two brothers, John and Robert Kennedy, who was also assassinated while campaigning for the presidency in 1968.

Hailed by Obama on Wednesday as "the greatest senator of our time," Kennedy's death leaves a void in the Senate, where he represented Massachusetts since 1963.

Talk has already begun over who would be Kennedy's replacement.

A 2004 state law requires a special election to be held within five months, but one of Kennedy's last wishes was for the law to be changed in order to allow for an interim appointment.

Massachusetts Governor Deval Patrick said he was open to the change and said the legislature was "seriously considering" the idea, which Kennedy suggested in a letter to Patrick and key legislators just a week before his death.

Kennedy's name is attached to countless pieces of congressional legislation over more than four decades, including reforms of education, immigration, civil rights and voting rights.

But his life-long goal - overhauling the US health insurance system - is still being debated in Congress. Legislation could be put to a vote in the coming months, and Democrats believe they could need every last vote to get major health care reforms approved in the 100- member upper chamber.

"Massachusetts needs two voices in the United States Senate," Patrick said in an interview with US broadcaster CNN, "particularly at a time when such profoundly important issues are before the Congress." (dpa)