He said a small number would protect oil fields while others would stay near Israel and Jordan.

His decision two weeks ago to withdraw US forces from the Syria-Turkey border region drew criticism even from some of his supporters.

Soon after, Turkey began an offensive against former US allies the Kurds.

The US president again defended his decision to withdraw, amid accusations he has betrayed Kurdish-led forces who have been an important partner in the battle against the Islamic State group.

"Why should we put our soldiers in the midst of two large groups, hundreds of thousands potentially of people, that are fighting? I don't think so," he said. "I got elected on bringing our soldiers back home."

But Mr Trump also said the US had been asked by Israel and Jordan to leave a small number of troops in "a totally different section of Syria".

In another part of the country he said US forces were needed to "secure the oil".

There are around 200,000 US troops deployed in conflict areas around the world, despite Mr Trump's promise to bring them home.

US troop numbers in the Gulf have reportedly increased by 14,000 since May, following attacks on Saudi oil tankers blamed on Iran.

Earlier this month, the Pentagon announced that about 3,000 American troops were being sent to "enhance the defence of Saudi Arabia".

Turkey moved against Kurdish-led forces in Syria with the aim of pushing them away from northern Syria and creating a "safe zone" for resettling up to two million Syrian refugees currently in Turkey.

Up to 300,000 people are reported to have fled their homes since the fighting started.

A ceasefire is currently in place to allow for the withdrawal of Kurdish-led forces from the area but is set to run out at 22:00 local time (19:00 GMT) on Tuesday.

Mr Trump has not ruled out the possibility of an extension.

In a separate development, three current and former defence officials told NBC that the Pentagon had begun drawing up plans for a quick withdrawal of all troops from Afghanistan in the event that Mr Trump orders an immediate withdrawal as he did with Syria.

Mr Trump has been heavily criticised over his decision to remove US forces from Syria.

The US House of Representatives voted overwhelmingly to condemn the move, with both Democrats and Mr Trump's fellow Republicans backing the resolution.

In an opinion piece in the Washington Post, Republican Mitch McConnell said it was a "strategic mistake".