* Israel leaders praise Sharon's security legacy
* U.S. Vice President Biden attends funeral
* Israel warns Hamas not to disrupt Sharon burial (Adds quotes and background)
By Crispian Balmer and Matt Spetalnick
JERUSALEM, Jan 13 (Reuters) - Israel paid homage to former Prime Minister Ariel Sharon at the first of two funeral services being held on Monday for a man celebrated as a war hero at home but seen by many in the Arab world as a war criminal.
U.S. Vice President Joe Biden and former British Prime Minister Tony Blair joined the sombre ceremony in front of the Israeli parliament, Sharon's coffin draped in Israel's blue and white flag, bathed in winter sunshine.
"We are accompanying to his final resting place today, a soldier, an exceptional soldier, a commander who knew how to win," said Israeli President Shimon Peres.
Sharon, 85, died on Saturday after spending the last eight years of his life motionless in a hospital bed, pitched into a coma by a stroke and far from the public gaze.
His death has reopened debate into his legacy, with foes denouncing his ruthless conduct in military operations while friends praised him as a strategic genius who had stunned the world in 2005 by pulling Israeli troops and settlers out of the Gaza Strip - a Palestinian territory in the south.
"The security of his people was always Arik's unwavering mission - a non-breakable commitment to the future of Jews, whether 30 years or 300 years from now," Biden said, using Sharon's nickname.
There was no direct mention of some of the controversies that have clung to Sharon's name through the years, although in his eulogy, Blair said a man widely known at home as "the bulldozer" had left "considerable debris in his wake".
Biden referred simply to his "mistakes", saying: "History will judge that he also lived in complex times, in a very complex neighbourhood."
The Israeli foreign ministry said dignitaries had come from 21 countries, mainly in Europe, but did not list any delegations from the Middle East, Africa or Latin America.
After the memorial service at parliament, Sharon's body was loaded into a military van for the drive to the family's farm in southern Israel, some 10 km (6 miles) from Gaza, for burial.
Prime Minister Benjamin Netanyahu, noting he had not always seen eye-to-eye with Sharon on policy matters, hailed the former leader's commitment to Israel's security.
"Arik understood that in matters of our existence and security, we must stand firm," Netanyahu said.
"Israel will continue to fight terror. Israel will continue to strive for peace, while protecting our security. Israel will act in every way to deny Iran the capability of arming itself with nuclear weapons."
Famously beefy and brusque, Sharon was widely hated by Arabs, particularly for Israel's 1982 invasion of Lebanon, when hundreds of Palestinian civilians in the refugee camps of Sabra and Shatila were killed by Israeli-allied Christian militiamen.
Sharon was forced to stand down as defence minister in 1983 after an Israeli investigation said he bore "personal responsibility" for not preventing the massacre.
Written off at the time, he soon bounced back and served as prime minister from 2001 until he was felled by a stroke.
Neither Netanyahu nor Peres mentioned the Lebanon war or disengagement from Gaza, which showed that Israel could roll back its occupation of the Palestinian territories given determined leadership. Both Biden and Blair hailed the pullout.
However, one of Sharon's friends, settler leader Zeev Hever, made clear the sense of hurt felt by some Israelis.
"Your disengagement in the final two years of your term from the path we had walked together was particularly difficult and painful," he told mourners.
Two years after Israel quit Gaza, the Islamist group Hamas seized control, calling for the destruction of the Jewish state. Israel has beefed up security for Sharon's burial and warned Hamas not to allow rocket fire during the ceremony.
"It was made clear to them that ... it would be a very bad day for anyone there to test Israel's patience," said an Israeli security source, who spoke on condition of anonymity.
A Reuters correspondent heard two explosions in northern Gaza on Monday morning which sounded like rocket impacts. An Israeli military spokeswoman said there had been no launches across the border. Israeli media said the blasts appeared to have resulted from Palestinian militants testing their weapons.
How to handle Gaza is among the sticking points in Israel's U.S.-sponsored peace negotiations with Palestinian President Mahmoud Abbas, Hamas's rival based in the occupied West Bank.
During his brief visit to Israel, Biden will discuss the so far fruitless diplomatic efforts with Netanyahu and Peres, U.S. officials said.
The vice president will also seek to ease Netanyahu's concerns about world powers' interim nuclear deal with Israel's arch-foe Iran, which takes effect on Jan. 20.
Sharon and Peres are the last of the so-called 1948-generation of leaders who played a prominent role in Israeli public life right from the foundation of the nation. ID:nL6N0KC0YR]
"He left us too soon. But the work of trying to reach peace continues," said Biden, hinting that had Sharon stayed healthy, he might have ended the decades-old Middle East conflict. (Additional reporting by Dan Williams, Editing by Jeffrey Heller)