Nearly 20 years after the American-led invasion that deposed Saddam Hussein, U.S. Defense Secretary Lloyd Austin said during an unannounced visit to Iraq on Tuesday that Washington was committed to maintaining its military presence in the nation.

Tens of thousands of Iraqi civilians died as a result of the 2003 invasion, which also caused instability that eventually laid the way for the establishment of the Islamic State extremists when the United States withdrew its forces in 2011.

Austin, the most senior official in President Joe Biden’s administration to visit Iraq, was the last commanding general of U.S. forces there after the invasion.

“U.S. forces are ready to remain in Iraq at the invitation of the government of Iraq,” Austin told reporters after meeting Iraqi Prime Minister Mohammed al-Sudani.

“The United States will continue to strengthen and broaden our partnership in support of Iraqi security, stability, and sovereignty,” he said.

Sudani later said in a statement that his government’s approach is to maintain balanced relations with regional and international governments based on shared interests and respect for sovereignty, and that “the stability of Iraq is the key to the security and stability of the region.”

The United States currently has 2,500 troops in Iraq – and an additional 900 in Syria – to help advise and assist local troops in combating Islamic State, who in 2014 seized swathes of territory in both countries.

Islamic State is far from the formidable force it once was, but militant cells have survived across parts of northern Iraq and northeastern Syria.