Users of the international exchange section of the prediction market platform Polymarket have had their funds stolen, due to a hack on an unnamed third-party service provider.

Polymarket has contacted law enforcement authorities and pledged to compensate all affected traders. It is still unclear how many users have been impacted. The company's US platform was not compromised.

Traders first reported on social media platforms on Thursday afternoon that they noticed unauthorized withdrawals from their accounts. In response, the company suspended trading on its international platforms.

Polymarket indicates that the company has resolved the related issues, and trading has resumed at 3 p.m. Eastern Time.

An informed source told CNBC that the incident stemmed from a hacker attack on the website performance monitoring platform DebugBear. In a post on X, DebugBear stated that the company was affected by the security incident. The aforementioned informed source mentioned that since DebugBear's headquarters is located in the UK, Polymarket has handed over the matter to the UK law enforcement authorities for handling.

DebugBear did not immediately respond to the request for comment.

The international prediction market exchange of Polymarket operates as a decentralized financial platform built on the Polygon blockchain and is not subject to U.S. regulation.

At the time of this interruption, there are only a few days left until the U.S. mid-term elections on November 3rd, and it is expected that both the international and U.S. exchanges of the company will see higher trading volumes by then.

A similar incident also occurred in June of this year. At that time, Polymarket stated that a third-party supplier had been "compromised," and the company would refund the affected users.

Disclosure:CNBC has a business relationship with Kalshi, which includes customer acquisition cooperation and a small amount of equity investment.