President Donald Trump has brushed off his Russian counterpart Vladimir Putin's description as a "killer", saying the US has "a lot of killers" and suggested that America was not so "innocent".

In an excerpt of an interview yet to be aired, Trump said he "respects" Putin, but that does not mean they will get along.

"I respect a lot of people, but that doesn't mean I'm going to get along with him. He's a leader of his country. I say it's better to get along with Russia than not. And if Russia helps us in the fight against ISIS, which is a major fight, and Islamic terrorism all over the world that's a good thing," Trump told Fox News' Bill O'Reilly.

When the interviewer called the Russian leader "a killer" over allegations of murders carried out by the Russian state, Trump said, "There are a lot of killers. We've got a lot of killers. What do you think? Our country's so innocent?" 

Trump and Putin agreed to establish "real coordination" against the ISIS during an hourlong discussion last week, which the White House hailed as a "significant start" to improving the strained ties between the two nations.

Just ahead of demitting office, Barack Obama had ordered sanctions on Russian spy agencies, closed two Russian compounds in the US and expelled 35 Russian diplomats that he claimed were really spies amid US intelligence reports that Moscow meddled in the 2016 election to help Trump become president.