Mobilized by calls on Facebook, thousands of Arab protesters marched on Israel's borders with Syria, Lebanon and Gaza on Sunday in an unprecedented wave of demonstrations, sparking clashes that left at least 15 people dead in an annual Palestinian mourning ritual marking the anniversary of Israel's birth.
Prime Minister Benjamin Netanyahu, who heads to Washington at the end of the week, said he ordered the military to act with "maximum restraint" but vowed a tough response to further provocations. "Nobody should be mistaken. We are determined to defend our borders and sovereignty," he declared in a brief address broadcast live on Israeli TV stations.
The violence showed Israel the extent of Arab anger over the Palestinian issue, beyond the residents of the West Bank and Gaza, and came at a critical time for U.S. Mideast policy.
Sunday's unrest -- which came after activists used Facebook and other websites to mobilize Palestinians and their supporters in neighboring countries to march on the border with Israel -- marked the first time the protests that have swept the Arab world in recent months have been directed at Israel.
The events carried a message for Israel: Even as it wrestles with the Palestinian demand for a state in the West Bank, Gaza and east Jerusalem -- areas Israel captured in the 1967 Mideast war -- there is a related problem of neighboring countries that host millions of Palestinians with aspirations to return.
Around midday, thousands of people approached the frontier, hoisting Palestinian flags, shouting slogans and throwing rocks and bottles at Israeli forces. When hundreds of people burst across the border fence into the Israeli-controlled town of Majdal Shams, surprised soldiers opened fire.
Israel's military spokesman, Brig. Gen. Yoav Mordechai, told Channel 2 TV he also saw "fingerprints of Iranian provocation and an attempt to use 'nakba day' to create conflict."
"It's our land," one of the infiltrators, Sufian Abdel Hamid, told Israel's Channel 2 TV. "We won't stop trying to come back."
