In Geneva, the United Nations human rights office condemned what it called the "appalling deadly violence" by Israeli forces and said it was extremely anxious about what might happen later. But at the moment there are no peace talks.
Mr Erdogan said the U.S. decision to move its embassy was not only a violation of United Nations resolutions and global law, but also a step away from the country's role as a mediator in the Middle East peace process.
The Hamas-run Gaza health ministry said that two Palestinians had been killed and over 160 were injured to varying degrees.
Ms Thornberry told MPs action was needed "to stop this vicious slaughter".
French Foreign Minister Jean-Yves Le Drian said Israel's need for security doesn't justify the "unacceptable violence" used by Israeli forces, while U.K. Minister for the Middle East Alistair Burt called the violence "shocking" and said "the large volume of live fire is extremely concerning". "I think he just gave it a fresh look and said, 'Well, why aren't we recognizing Jerusalem?".
Israeli PM Benjamin Netanyahu said his military was acting in self-defence against Gaza's Islamist rulers, Hamas, who he said wanted to destroy Israel.
The French president, Emmanuel Macron, condemned "the violence of the Israeli armed forces against protesters" in a telephone call with the Palestinian president, Mahmoud Abbas, and Jordan's King Abdullah II.
Palestinians hurled stones and incendiary devices and approached the border fence.
An Israeli government spokesman had no immediate reaction to the cascade of criticism.
Mr Netanyahu defended his military, saying: "Every country has an obligation to defend its borders. That's the difference between Israel's culture of life and Hamas's culture of death in Gaza".
Support for the embassy move and the timing ran highest among Israeli Jews who identified as "national religious" (89 percent) as opposed to Haredi (77 percent), traditional (84 percent), or secular (60 percent).
Haley also insisted the violence had nothing to do with the opening of a United States embassy in contested Jerusalem, saying that Gaza's Hamas rulers have been inciting violence there for years.
A senior Hamas leader, Khalil Al-Hayya, was quoted in Reuters as saying the protest purposefully coincided with Trump's "deplorable crime of moving the U.S. Embassy to Jerusalem". "We call for an worldwide inquiry led by the United Nations", Michel said in a joint statement with Foreign Minister Didier Reynders.
On Monday, the bloodiest day in Gaza in years took place as Israel celebrated another coup - Washington's relocation of its Israeli embassy to Jerusalem from Tel Aviv.
The Palestinian president, Mahmoud Abbas, called the new embassy "a USA settlement in East Jerusalem".
What is the Gaza Strip?
The commemoration highlights the violent campaign that led to the expulsion of hundreds of thousands of Palestinians from their villages.
Egypt administered Gaza for the next 19 years but Israel occupied it in the 1967 Arab-Israel war. The Palestinian ambassador Riyad Mansour accuses the USA of helping Israel act as if it's above the law.
Austen condemned the involvement of Hamas in the clash, pointing out that the group is "a listed terrorist organization". Israel says the blockade is necessary to prevent Hamas from acquiring weaponry and attacking the Jewish state. Almost three-quarters (73 percent) of them said they support not only moving the embassy, but doing so now.
The Gaza Strip is impoverished and the United Nations has warned it is on the verge of total collapse.
KELEMEN: She says Hamas has been encouraging Palestinians in Gaza to try to breach the border fence with Israel. They want to enter Israeli territory to harm the citizens of Israel, kidnap soldiers or attack residential areas.