BEIRUT, Lebanon — The leader of the Lebanese militant group Hezbollah said on Monday that the group would return its focus to fighting on behalf of Palestinians, saying it had prevailed in other regional battles against Syrian insurgents and the Islamic State.

Ridiculing Syrian insurgents as “tools of the U.S.A. and Israel,” the Hezbollah leader, Hassan Nasrallah, said that “Jerusalem, Palestine and the Palestinian people will return to being the priorities” for Hezbollah, adding that the group would “dedicate all its time to resistance.”

Speaking via a video feed at a rally in Beirut, the Lebanese capital, that was organized to protest President Trump’s decision to recognize Jerusalem as Israel’s capital, Mr. Nasrallah called on Arab and Muslim countries to abandon their pursuit of normalizing relations with Israel by evicting the country’s embassies and cutting diplomatic ties.

“Today we are witnessing a true intifada,” or uprising, Mr. Nasrallah told the crowd, speaking of protests that have spread throughout the Palestinian territories of the West Bank and Gaza. “Muslims and Christians are all united to defend their holy sites in Jerusalem.”