He warned that Mr Putin could try to destabilise a Nato member by using a rebel militia as in eastern Ukraine, or other forms of ambiguous warfare.
In the absence of an overt Russian attack, some Nato members could be reluctant to invoke Article 5 of the Washington treaty, under which an attack on one member is an attack on all.
Once Article 5 is gone, our alliance is over, Gen Hodges said.
He called for American tanks to be positioned in countries along Natos eastern flank, as a deterrent to Mr Putin.
Just months after moving its last tanks out of Europe, the US has decided to send some 220 Abrams tanks and Bradley fighting vehicles back in response to the Ukraine crisis.
Gen Hodges said he had proposed positioning some of the tanks in Poland, Lithuania, Latvia, Estonia, Romania and Bulgaria.
And the US has already agreed to send troops to Poland and the three Baltic states.
Gen Hodges called for Nato countries to maintain defence spending in the face of the Ukraine crisis.
The chief of staff of the US army, Gen Raymond Odierno, said he was very concerned earlier this week after David Cameron refused to commit to maintaining defence spending at Natos agreed target of 2 per cent of GDP.
But Gen Hodges said he was sure the UK would continue to meet the 2 per cent target.
Follow this link:
Vladimir Putin wants to destroy Nato, says US commander in Europe Ben Hodges