The US has announced the end of its 23-year military presence in Iraq, as it shifts its focus to expanding the war against Iran.

US President Donald Trump and Iraqi Prime Minister Ali al-Zaidi said at the White House on Tuesday that US forces will leave Iraq by September 30, ending a deployment that began with the 2003 invasion and the overthrow of then-Iraqi President Saddam Hussein and later continued under the banner of counterterrorism.

Around 2,000 US servicemen are believed to still be stationed in Iraq.

”We don’t think we need the military there anymore,” Trump said, arguing that Iraq’s security environment has changed after months of US-Israeli strikes “destabilized” Iran.

Al-Zaidi confirmed that US forces will be gone by the end of September and that “American companies will enter” instead.

Trump said the relationship with Iraq will now focus on investment and energy, citing the country’s oil reserves. He said the two countries are “going to be doing a lot of deals” and that the US is “going to be taking out a lot of oil.”

The US invaded Iraq in March 2003, claiming that Saddam Hussein possessed weapons of mass destruction and had links to terrorist groups. Although the weapons were never found, the US presence grew to more than 170,000 troops by 2007.

In 2011, most combat forces left, but the US returned in 2014 after Islamic State (IS, formerly ISIS) captured large areas of Iraq and Syria.

Critics argued that the Iraq invasion was launched on false pretenses, destabilized the country, helped create the conditions for the rise of IS, and was “largely about oil,” which former Federal Reserve Chairman Alan Greenspan acknowledged in his memoirs.

Trump has been far more open about this than past administrations, and has argued that America should have “taken the oil” in Iraq, and that US forces in Syria would be “keeping the oil.”

Last week, Trump resumed military strikes on Iran and has refused to rule out a ground operation by allied forces and the potential capture of Kharg Island, Iran’s main oil export hub, in order to “take the oil.”