Such strikes aim to disrupt "people's ability to stay connected, study, work", says Ukraine's president.

Experts say the hack could leave agents vulnerable to scams, blackmail and targeted attacks.

The pontiff delivered the warning on the first day of his trip to France on Friday.

Critics have questioned the reliability of the data, warning it could result in US citizens being wrongly removed from electoral rolls.

Opposition to building the 250-foot arch, and using it for military purposes, is growing with one Democrat blasting Trump's plans as "foolhardy".

A law establishing voluntary military service came into effect in January, but protest organisers fear compulsory service could follow.