23 towns in Texas had their computer systems hacked and their data held hostage in a large-scale coordinated ransomware attack August 16, the Texas Department of Information Resources said.

The attack was launched by a "single threat actor" and is the largest ransomware attack so far based on the number of areas affected, according to a cybersecurity analyst who spoke with The New York Times. It may be the largest coordinated ransomware attack on cities to date, that analyst added.

It's unclear whether the computer systems in the affected town had sufficient security measures, or whether they have backups of their data. It's also unclear if any services were disrupted.

It's also unknown how much money the attacker is demanding to end the attack.

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Twenty-three towns in Texas had their computer systems hacked and their data held hostage in a large-scale coordinated ransomware attack August 16, the Texas Department of Information Resources said in a statement.

The attacker is holding the data in the towns' computer systems for ransom. The attack was launched by a "one single threat actor," the DIR said.

The alternative to paying the ransom would be for each town to restore from older data backups, but it's unclear whether backups exist. It's also unclear whether the towns had sufficient security measures in place to mitigate such an attack in the first place.

Speaking with The New York Times, Allan Liska, an analyst with the cybersecurity firm Recorded Future, said the Texas ransomware attack was the largest so far, and possibly the first time he's seen a coordinated attack of this nature.

The DIR revealed little information about the attacks. It's not known which towns or departments were affected, whether any town services were affected, nor how much the attackers are demanding.

Texas' state systems were not part of the attacks, the DIR said.

The DIR declined to comment beyond the news release.

In May, Baltimore had 10,000 of its computers affected by a ransomware attack, when the attacker demanded a $100,000 payment in Bitcoin to release the data.

In June two cities in Florida were also affected by a ransomware attack.

Lake City and Riviera Beach paid over $1 million to the attackers to release the data stored in the city systems. Lake City paid $500,000 worth of Bitcoin. Riviera Beach paid $600,000.