US President Donald Trump will relocate some American forces being withdrawn from Syria to a base in Iraq, where he says they will be able to monitor Iran.

In an interview with CBS to be aired Sunday, Trump defends his decision to pull US troops out of Syria and says the withdrawal is happening gradually as “we have to protect Israel.”

Trump’s abrupt announcement in December he would pull all American soldiers from Syria set of alarm bells in Israel, which has being carrying out a campaign to prevent an Iranian military presence there.

Asked why he would keep troops in Iraq despite his criticism of the 2003 US invasion of the country, Trump says, “We spent a fortune on building this incredible base. We might as well keep it.”

“And one of the reasons I want to keep it is because I want to be looking a little bit at Iran because Iran is a real problem,” he adds.

Trump insists the base is meant only to “watch” Iran, not to carry out a strike against it.

“All I want to do is be able to watch. We have an unbelievable and expensive military base built in Iraq. It’s perfectly situated for looking at all over different parts of the troubled Middle East rather than pulling up,” he says.

The US president also addresses his public dispute with intelligence chiefs last week after they testified Iran was in technical compliance with the 2015 international accord meant to limit its nuclear program.

“When I look at Iran, I look at Iran as a nation that has caused tremendous problems,” he says. “So when my intelligence people tell me how wonderful Iran is – if you don’t mind, I’m going to just go by my own counsel.”