Bitter Palestinian rivals marched together Saturday in a rare show of unity as they marked 62 years of displacement in the war surrounding Israel's creation.Loyalists of rival groups Hamas and Fatah held Palestinian flags and a giant key symbolic of their hoped-for return as part of annual commemorations of what they call the "catastrophe," or nakba in Arabic. The names of the villages and towns emptied during the war were written across the key, alongside the slogan "We will return."The plight of the refugees — who fled or were driven from their homes during the 1948 Israeli-Arab war — is one of the most emotionally charged issues for Palestinians and Israel to resolve.Palestinian negotiators have demanded at least partial repatriation. Israel has refused, saying an influx of refugees would dilute Israel's Jewish majority and threaten the existence of the state.Gaza's Hamas rulers invited their Fatah rivals to participate in Saturday's march, a rare gesture from the Islamic militant group since it seized Gaza and ousted Fatah forces in June 2007. In previous years, different Palestinian factions organized their own events, highlighting their inability to work together on key issues.No political speeches were made — an apparent nod to the fundamental ideological differences between Hamas and Fatah. Marchers also were asked not to raise the flags of their parties. Some Fatah women got around the ban by wearing yellow headscarves, the color of their movement.Some 4.7 million Palestinians refugees and their descendants are scattered across the West Bank, Gaza, Lebanon, Jordan and Syria, according to UN figures. About one-third still live in UN-supported refugee camps. At the Gaza rally, marcher Amina Hasanat, 50, held up tattered documents she said showed her family owned a house and land in what is now the southern city of Beersheba in Israel. "They (the Jews) can go back to where they came from, and we will return to our homes and lands," Hasanat said.In the West Bank city of Ramallah, hundreds of Palestinian motorists and pedestrians halted as a one-minute siren wailed to mark the anniversary. Smaller marches took place in other West Bank towns and in east Jerusalem.In Lebanon, the militant Hezbollah group, which fought a guerrilla war against Israeli forces until they withdrew from south Lebanon in 2000, said in a statement that "resistance and sacrifice" are the only way to retake Arab-claimed lands."At the 62nd anniversary of nakba, we call upon all Arabs to keep the Palestinian cause alive in the eyes and hearts of all generations," said Hezbollah, which also battled Israel in a 34-day war in 2006 that left some 1,200 Lebanese and 160 Israelis dead.Egypt, meanwhile, opened its usually closed border crossing with Gaza on Saturday for the first time in 75 days to allow medical patients and Gazans with residency abroad to leave the blockaded territory. Israel and Egypt have been keeping Gaza's borders largely closed since the 2007 Hamas takeover, but Egypt periodically opens its Rafah passenger terminal with Gaza to allow hardship cases to cross.Gaza's Interior Ministry said some 8,000 Gazans had registered to leave during the scheduled four-day opening. By mid-afternoon Saturday, seven buses had crossed from Gaza into Egypt.On Gaza's border with Israel, the body of a 78-year-old Palestinian man was found shot dead, said Dr. Adham Abu Salmiyeh of the northern Gaza hospital Kamal Adwan.An Israeli military spokesman said forces confirmed shooting a man who approached the border fence on Friday evening. Israel has declared a swath of land on the Gaza side of the border as a no-go zone, and those approaching it risk getting shot by Israeli patrols. Israel says it's a security measure, to prevent infiltration and attacks by Gaza militants.