“The Israelis hit back, and they should hit back,” Trump told reporters on Air Force One on Wednesday en route to a meeting of Asia-Pacific leaders in South Korea after a visit to Japan. “When that happens, they should hit back.”

Prime Minister Benjamin Netanyahu on Tuesday ordered “forceful strikes” against Hamas in response to attacks on Israeli soldiers in Gaza, testing an agreement whose core points included both Hamas and Israeli forces stopping their attacks.

The bombing killed at least 20 people late Tuesday, the official Palestinian news agency WAFA said, citing medical sources. The Associated Press reported that the sound of tank fire and explosions could be heard in Gaza City and elsewhere in the territory. Israel notified the US in advance of the strikes, the AP said.

Yet Trump said that “nothing” is going to jeopardise the ceasefire that he brokered just over two weeks ago, adding that Hamas is only “a very small part of peace in the Middle East.”

“They said they would be good, and if they’re good, they’re going to be happy, and if they’re not good, they’re going to be terminated. Their lives will be terminated.”

Trump reiterated that Hamas must disarm, one of the points of his 20-point plan accepted by the group, designated as a terrorist organisation by the US and the European Union.

“If they don’t behave, they get taken out,” Trump said.