Texas has been hit with a wave of ransomware attacks targeting at least 20 local government entities.

The Texas Department of Information Resources (DIR) said late Friday that it is leading the response to a 'coordinated ransomware attack' that is crippling critical government infrastructure across the state.

Ransomware disables computer networks and holds them hostage in demand for payment.

Workers are seen inside the Texas Division of Emergency Management, State Operations Center in Austin in a file photo

'Currently, DIR, the Texas Military Department, and the Texas A&M University System’s Cyberresponse and Security Operations Center teams are deploying resources to the most critically impacted jurisdictions,' the department said in a statement.

WHAT IS RANSOMWARE? Cybercriminals use 'blockers' to stop their victim accessing their device. This may include a mesage telling them this is due to 'illegal content' such as porn being identified on their device. Anyone who has accessed porn online is probably less likely to take the matter up with law enforcement. Hackers then ask for money to be paid, often in the form of Bitcoins or other untraceable cryptocurrencies, for the block to be removed. In May 2017, a massive ransomware virus attack called WannaCry spread to the computer systems of hundreds of private companies and public organisations across the globe. Advertisement

The department urged local jurisdictions who have been impacted to contact their local TDEM Disaster District Coordinator.

'DIR is fully committed to respond swiftly to this event and provide the necessary resources to bring these entities back online,' the agency said.

It was not immediately clear which cities had been impacted by the attacks and what entity is suspected of perpetrating them.

A spokesman for DIR did not immediately respond to a request for comment from DailyMail.com on Saturday.

The attack came within hours of a massive failure of U.S. Customs and Border Protection computers that caused huge travel delays across the country - although the federal agency has insisted that the outage was not 'malicious' in nature.

'The affected systems are coming back online and travelers are being processed. CBP will continue to monitor the incident. There is no indication the disruption was malicious in nature at this time,' CBP said in a statement at 6.30pm ET on Friday.