The Palestinians who forced their way across Israel's border on Sunday turned back the clock on the Middle East conflict, putting centre stage the refugee question that many believed would be negotiated away.

Protests at Israel's borders with Syria and Lebanon also cast the spotlight on a diaspora marginalised in Palestinian politics since Yasser Arafat moved from exile to the Israeli-occupied West Bank and Gaza Strip two decades ago.

It was not without cost -- at least 13 demonstrators were shot dead. Organised by members of a refugee community claiming a right to return to their old homes in modern-day Israel, the protests generated pride and delight in the West Bank and the Gaza Strip, home to some 2 million members of that diaspora.

When some protesters breached the frontier with Syria, in scenes broadcast live on satellite TV, to Palestinians it seemed the impossible had happened, even if only for a brief while.

"This is a message to anyone who thinks of giving up the right of return," said Abdel Qader al-Beshawi, a 50-year old Palestinian from Balata refugee camp in the West Bank, captured along with Gaza in the 1967 Middle East war.

His family were forced from their home in the seaside town of Jaffa in the 1948 war that helped set the borders of the state of Israel and sparked the departure of hundreds of thousands of Palestinian refugees to surrounding Arab lands.

"For the first time I felt that that we could return to our town after years of deep despair," said Beshawi, one of some 4.8 million Palestinian refugees registered with the U.N. in Jordan, Lebanon, Syria and the occupied Palestinian territory.

"INALIENABLE RIGHT"

Like the fate of Jerusalem, the refugee question is one of the issues at the heart of the Palestinian-Israeli conflict.

But the refugees have long suspected that their longed-for return was being negotiated away in the Middle East peace process aimed at the establishment of a Palestinian state alongside Israel in the West Bank and the Gaza Strip.

To Israel, the idea of a mass return of refugees is a non-starter that would destroy the Jewish state.

Israel says any solution to the refugee question should be found within the borders of a future Palestine and described Sunday's clashes as as cynical provocation inspired by its foe Iran.

Syria, an ally of Iran, has always kept tight control of its border with Israel and, even with current internal unrest faced by the Damascus government, observers said it was hard to imagine Sunday's protest happening without official approval.

To the Palestinians, the protests cut to the very core of their struggle, falling on the day they call the "Nakba", or catastrophe, which marks the creation of Israel 63 years ago.

The right of return has been the main theme of posters put up all over Ramallah to mark this year's Nakba anniversary.

Details of peace talks between Israel and the Palestine Liberation Organisation (PLO) have spoken of the return of a token number of refugees to Israel and a solution agreed upon by both sides. To refugees, such ideas amount to a sell-out.

Hamas, which governs in Gaza, is not part of the PLO and has always rejected the idea of a negotiated peace deal with Israel.

"The crowds we have seen in Palestine, Egypt, Syria, and Lebanon is an evidence of the imminent victory and return to the original homes as promised by God," said Taher Al-Nono, spokesman of the Hamas government in Gaza.

Leading members of the Palestine Liberation Organisation said Sunday's protests gave new life to the demand for the right of return to homes lost when Israel was created.

"The right of return is a fixed, inalienable right and the Palestinians revived it this time on the Nakba anniversary in its own special way, inspired by what happened in the Arab states," said Tayser Khaled, a member of the PLO executive.

(Additional reporting by Nidal al-Mughrabi in Gaza; Editing by Matthew Jones)