JERUSALEM, May 11 (JTA) — Israel held its 49th Independence Day celebrations amid an unpromising climate for restarting Israeli- Palestinian negotiations. The state ceremony at Jerusalem’s Mount Herzl on Sunday evening opened with the theme, “100 years of Zionism,” to commemorate the century that has passed since the first session of the Zionist Congress was held in Basel, Switzerland, to set out the goals of the Zionist movement. The start of Independence Day officially marked the end of Israel’s Memorial Day, which commemorated the 18,538 men and women who fell in defense of the state since the 1948 War of Independence. The total included 328 people who died during the past year. For the first time, this year’s Memorial Day observances recalled civilians killed in terrorist attacks. As a siren brought the country to a standstill Sunday in memory of the fallen, Israeli leaders and military officers stressed that a strong Israel was essential for the country’s future. “We are moving surely, step by step, toward an era of acceptance by our neighbors of Israel’s existence,” Prime Minister Benjamin Netanyahu said at the main state memorial ceremony at the Mount Herzl military cemetery. He said that a strong Israeli army was “the true basis for the hope of peace.” Meanwhile, U.S. Middle East envoy Dennis Ross continued efforts to revive the stalled Israeli-Palestinian peace talks. His mission to the region, which began last week and was his second in a month, was to be extended by several days, American officials said. Ross, who held a series of separate meetings last week with Netanyahu and Palestinian Authority leader Yasser Arafat, is encountering hardened positions on both sides. Israeli-Palestinian contacts all but stopped in mid-March, when Israel started construction of a new Jewish neighborhood at Har Homa in southeastern Jerusalem. The Palestinians have been calling for a halt to the project, and to settlement expansion, as a precondition for restarting negotiations. Israel also has a precondition — the resumption of intelligence-sharing. Less than optimistic about immediately finding a formula to bring the two sides back to the table, Ross said this week that it could take weeks before Israeli-Palestinian negotiations resume. Netanyahu said he believed there were still many hurdles to be overcome before the talks would get back on track. “They cannot expect us to make all the concessions, while they make none,” Netanyahu told Israel Radio, adding that it was too early to decide whether Ross’ shuttle was a success or failure. Netanyahu also discussed Israeli-Syrian negotiations, which have been stalled since March 1996, saying that Washington would play a key role in restarting the talks. The prime minister said that there had been recent contacts in which Damascus signaled interest in renewing the talks, but added that it was too soon to judge Syria’s seriousness. Senior Israeli army officers warned that if the peace option failed to break the deadlock over the future of the Golan Heights, Damascus could still consider the war option. Syrian words and actions are “pointing to the possibility of Syria’s using force to achieve political aims if the path of peace does not succeed,” Israel Defense Force chief of staff Lt. Gen. Amnon Shahak told Army Radio. Israel imposed a closure on the West Bank and Gaza Strip Saturday evening, when Memorial Day began, as a precaution against terrorist attacks. The closure was to be lifted Tuesday morning, after Independence Day ended.