U.S. President Donald Trump issued a stark warning to Israel over annexing the West Bank in an interview published Thursday, as visiting Secretary of State Marco Rubio voiced confidence that a U.S.-backed ceasefire in Gaza would hold.

Trump's remarks were made to Time magazine by telephone on Oct. 15 — just days after the Gaza truce plan he spearheaded took effect — but were only published on Thursday.

"It won't happen," Trump said when asked about calls in Israel to annex the Palestinian West Bank, which has been occupied by Israel since 1967. "It won't happen because I gave my word to the Arab countries."