The US intelligence community accuses Russia of interfering in the 2016 presidential election. Mr Pompeo said he believes Russia will target the 2018 US mid-term elections.
"I have every expectation that they will continue to try and do that but I'm confident that America will be able to have a free and fair election (and) we will push back in a way that is sufficiently robust that the impact they have on our election won't be great."
Talking about China, Mr Pompeo said: "The Chinese have a much bigger footprint upon which to execute that mission than the Russians do."
"China's reach ranged from traditional espionage (human and cyber)," Mr Pompeo said while accusing Beijing of influencing American companies seeking access to its market, the BBC report said on Tuesday.
Earlier this year, former CIA officer Jerry Chun Shing Lee was arrested on charges of retaining classified information in a case thought to be connected to the dismantling of the agency's spy operations in China.
In the two years before Jerry's arrest, some 20 informants had been killed or jailed.
"We can watch very focused efforts to steal American information, to infiltrate the US with spies -- with people who are going to work on behalf of the Chinese government against America," he said.
Mr Pompeo said that even though there has been co-operation in counter-terrorism efforts between Washington and Russia, he still saw Moscow primarily as an "adversary".
"I haven't seen a significant decrease in their activity," he said.
He also said North Korea may have the ability to strike the US with nuclear missile