The U.K. Parliament became the latest Western government to be targeted in a cyber attack Friday. Parliamentary officials said the attack was aimed at all parliamentary email accounts and hackers sought to identify weak passwords.

It prompted parliament to temporarily block all remote access to the email accounts of MPs, members of the House of Lords and parliamentary staff. More than 10,000 Westminster staff were told to change their passwords after the “sustained and determined” effort.

The sun sets over Britain’s Houses of Parliament on March 17, 2005 in London, England. Photo by Scott Barbour/Getty Images

Those responsible for Friday’s attack have not been identified, but a British security officialthe attack appeared to have been “state sponsored.”

Last year’s attack on DNC email servers was the work of Russian state backed hackers, U.S. intelligence agencies declared, while only last month the U.K’s National Health Service was targeted by hackers from North Korea, according to British security officials.

The German, French and Norwegian governments have all been targeted by cyber attacks in recent years.

The U.K. has long been aware of the threat of cyber attacks.

In 2015, the government’s National Security Strategy said that the threat from cyber-attacks from both organized crime and foreign intelligence agencies was one of the “most significant risks to UK interests.”

After Friday’s attack, Tory MP Henry Smith on Twitter quipped: “Sorry no parliamentary email access today – we’re under cyber attack from Kim Jong Un, (Vladimir) Putin or a kid in his mom’s basement or something…”

Other MPs speculated that blackmail could have been a motive.

Tory MP Andrew Bridgen told the Press Association that such an attack “absolutely” could leave some people open to blackmail. “Constituents want to know the information they send to us is completely secure,” he said.

The attack follows reports of cabinet ministers’ passwords and email addresses being for sale online by Russian hackers selling a haul of stolen data.

The international trade secretary, Liam Fox, told ITV News the attack was a “warning to everyone we need more security and better passwords. You wouldn’t leave your door open at night”.

In an interview with the BBC, he added: “We know that there are regular attacks by hackers attempting to get passwords. We have seen reports in the last few days of even Cabinet ministers’ passwords being for sale online. We know that our public services are attacked, so it is not at all surprising that there should be an attempt to hack into parliamentary emails.”