At least 37 people were killed and more than 1,000 wounded during an attempt by Palestinians to cross the border from Gaza to Israel.
The New York Times, citing the Health Ministry in Gaza, put the death toll at 37.
Protests on the border have been taking place for weeks but appeared to rise in intensity ahead of the scheduled opening on Monday of the new U.S. Embassy in Jerusalem.
President TrumpDonald TrumpRobert Gates says 'extreme polarization' is the greatest threat to US democracy Cassidy says he won't vote for Trump if he runs in 2024 Schiff says holding Bannon in criminal contempt 'a way of getting people's attention' MORE decided to move the U.S. Embassy from Tel Aviv to Jerusalem, a controversial step opposed by other nations given the disputed status of Jerusalem, which both Israel and Palestinians recognize as their capital.
Israeli troops seeking to keep Palestinians out of Israel used tear gas and live ammunition to keep Palestinians from scaling a fence across the border.
Video shows waves of protestors seeking to cross. Reports indicated many children were among those killed and wounded.
Israelis said some protesters threw explosives or sent kites lit with fire across the border, according to the Times.
“Even if the fence is breached, we will be able to protect Israeli civilians from attempts to massacre or kidnap or kill them,” a spokesman for Israel’s military, Lt. Col. Jonathan Conricus, told The Associated Press.
Trump's decision to move the U.S. Embassy to Jerusalem left Palestinians saying the United States could no longer position itself as a peacemaker.
Palestinians have sought to make the eastern part of Jerusalem the capital of a Palestinian state. Given the Trump decision, Palestine's leaders say they can no longer take the U.S. seriously as a mediator.
Reuters reported Sunday that diplomats from western European Union nations did not take part in the launch event commemorating the embassy's move.
Ivanka TrumpIvanka TrumpGrisham: Time in Trump administration 'will follow me forever' Grisham: Jared Kushner, Ivanka Trump saw themselves as 'shadow president and first lady' Grisham says her 'enabling' cost lives during pandemic MORE and Jared KushnerJared Corey KushnerHillicon Valley — Presented by LookingGlass — Hackers are making big money Kushner associate pardoned by Trump in plea discussions over cyberstalking charges Biden has an opportunity to put his own stamp on Arab-Israeli relations MORE are attending the commemoration.
Trump in a recorded message said the moving of the embassy had “been a long time coming.”
"We extend a hand in friendship to Israel, Palestinians and all of their neighbors. May there be peace,” the president said.
"This city and its entire nation is a testament to the unbreakable strength of the Jewish people,” Trump added.
The Times reported that the clashes on the border are expected to get even larger on Tuesday, with thousands more likely to try to traverse the barrier.
--Updated at 9:33 a.m.