MOSCOW (REUTERS) - The Kremlin accused US presidential contender Hillary Clinton on Wednesday of making unfounded and inappropriate remarks by including Russia among countries she said were sponsoring hacking.

Clinton said on Tuesday that hacking posed a broad threat to US security and business and that Russia, North Korea, Iran and China had "directly or indirectly sponsored" hacking.

Asked about her comments, Kremlin spokesman Dmitry Peskov told reporters: "This is an absolutely inappropriate statement and an unfounded accusation."

"Hacking is an international problem and speaking of government sponsorship is a completely unfounded accusation," he said, describing the comments as "unconstructive" in the context of calls for cooperation in the fight against cybercrime.

China has played down Clinton's remarks against Beijing.

Clinton, a Democrat, said her worries started when as US secretary of state she heard businesses express concern that confidential information was being "vacuumed up through intrusive hacking".

She has also said the United States must be "much smarter" about how it deals with Russian President Vladimir Putin, saying there is no substitute for "constant engagement".