US Secretary of State Mike Pompeo said Saturday he was concerned by 'malicious' cyber attacks that have  targeted Czech hospitals battling the novel coronavirus.

"As the world battles the COVID-19 pandemic, malicious cyber activity that impairs the ability of hospitals and healthcare systems to deliver critical services could have deadly results," Pompeo said.

"Anyone that engages in such an action should expect consequences," he added in a statement obtained by AFP.

Several Czech hospitals have recently reported cyber attack attempts which they have withstood.

"The situation is quiet now, we have seen individual incidents which have been prevented," Czech Health Minister Adam Vojtech said on Friday.

"However, we still have to be very cautious," he added.

The Czech National Cyber and Information Security Agency NUKIB on Thursday warned against attacks which it expected "in the next few days".

Hospitals in the eastern Czech cities of Olomouc and Ostrava as well as several others then announced attacks on their computer systems which they averted.

NUKIB did not say where the attacks might come from. In a report last year, it singled out Russia and China as posing the biggest threat to Czech cyber security.

"We call upon the actor in question to refrain from carrying out disruptive malicious cyber activity against the Czech Republic's healthcare system or similar infrastructure elsewhere," Pompeo said.

"We also call upon all states not to turn a blind eye to criminal or other organizations carrying out such activity from their territory," he added, vowing "zero tolerance" for such attacks.

The Czech Republic, an EU and NATO member of 10.7 million people, reported 6,553 confirmed COVID-19 cases, including 176 deaths, on Saturday morning.

The United States has declared more than 700,282 cases and 36,773 deaths.