New York: US President Donald Trump has called Turkey's invasion of northern Syria a "bad idea", while distancing himself from the Kurds because they did not help the US in World War II - specifically the invasion of Normandy.
Trump's reaction was far milder than that of senior Republicans in Washington, who blasted the Turkish incursion and redoubled their attacks on the President for withdrawing US troops from the region.
The unusual level of criticism from Trump's political allies comes as he faces an impeachment battle with Democrats in Congress and new polls showing a majority of Americans now support his removal from office.
Turkish President Recep Tayyip Erdogan announced the start of the military action on Twitter on Wednesday local time (Thursday AEDT), saying the aim was to eliminate a "terror corridor" on his country's southern border.
"The United States does not endorse this attack and has made it clear to Turkey that this operation is a bad idea," Trump said in a statement shortly afterwards.
"There are no American soldiers in the area.
"From the first day I entered the political arena, I made it clear that I did not want to fight these endless, senseless wars - especially those that don't benefit the United States."
Trump said that Turkey had committed to protecting civilians and would ensure that Islamic State fighters in the region remained in prison.
He announced earlier in the week that US troops would withdraw from the region, an announcement that stunned the Washington foreign policy community.
Speaking to reporters at the White House, Trump said: "The Kurds are fighting for their land.
"And as somebody wrote in a very, very powerful article today, they didn't help us in the Second World War, they didn't help us with Normandy, as an example.
"They mentioned names of different battles. But they're there to help us with their land and that's a different thing."
Trump appeared to be referring to an article in the Town Hall website by conservative writer Kurt Schlichter that included a reference to the Kurds and Normandy.
Republican Senator Lindsey Graham, usually a vociferous defender of the President, said the Turkish invasion was a "disaster in the making".
"Pray for our Kurdish allies who have been shamelessly abandoned by the Trump Administration," he wrote on Twitter.
"This move ensures the re-emergence of ISIS."
Republican congresswoman Liz Cheney, the daughter of former vice-president Dick Cheney, said in a statement that Trump's decision would have "sickening and predictable consequences".
"The US is abandoning our ally the Kurds, who fought ISIS on the ground and helped protect the US homeland," she said.
"This action imperils American security and that of our allies.
"Congress must and will act to limit the catastrophic impact of this decision."
A new poll by Fox News showed that 51 per cent of respondents want Trump impeached and removed from office - a record high.
