Pro-Palestinian protesters at a demonstration organized by a Moroccan Islamist association in Casablanca on Sunday.CreditYoussef Boudlal/Reuters

CASABLANCA, Morocco — More than 10,000 Moroccans chanting "death to Israel" took to the streets of Casablanca on Sunday to protest the United States' decision to move its embassy in Israel to Jerusalem.

The marchers carried Palestinian flags and placards that called Jerusalem "Palestine's eternal capital." Most appeared to be Islamists, with women wearing head scarves and marching separately from the men.

The United States opened its embassy in Jerusalem on May 14, relocating it from Tel Aviv — a move that reversed decades of United States policy, delighted Israel and infuriated Palestinians.

The status of Jerusalem is one of the thorniest obstacles to forging a peace deal between Israel and the Palestinians, who with broad international backing want East Jerusalem, captured by Israel in the 1967 Middle East war, as their capital.

Israel regards all of the city, including the eastern sector it annexed after the 1967 conflict, as its capital. The Trump administration has said the city's final borders should be decided by the parties.

On the day the United States opened its new embassy — the 70th anniversary of the formation of Israel — Israeli troops killed 60 Palestinian demonstrators near the border in Gaza.

It was the bloodiest day in Gaza since demonstrations began nearly two months ago in protest of Israel's economic blockade of the territory. A mass attempt by Palestinians to cross the border fence separating Israel from Gaza was met with rifle fire from Israeli soldiers.

Protests against the embassy move were also held that day on the West Bank.

The Casablanca demonstration on Sunday was called by a coalition of four parties including the Islamist opposition group Al Adl Wal Ihsane, or Justice and Charity, which is considered Morocco's most powerful opposition group in terms of rallying supporters on the street.

Mr. Trump formally recognized Jerusalem as Israel's capital in December, though administration officials said this month that the American ambassador to Israel would not yet work permanently out of his new office there. Instead the ambassador, David M. Friedman, will split his time between Jerusalem and Tel Aviv, allowing him to continue to host officials whose countries oppose the American embassy move.

Most of the international community is against the move, but Guatemala, Paraguay and Honduras are relocating their embassies to Jerusalem.