A group of four armed thieves broke into the art fair TEFAF Maastricht this morning, smashing the glass case of one of the exhibitors in an attempt to rob fine jewels that were on display there.

The incident occurred on Tuesday at around 11:30 a.m. Central European Time and the police were on the scene within minutes, according to a statement released by the fair. Nobody has been reported as injured.

The Limburg police have also confirmed the news on Twitter, saying that two arrests have been made on the A2 road. Several roads in and around Maastricht were temporarily closed for the investigation.

According to images and video circulating on Twitter, it appears that the booth of the London dealer Symbolic & Chase had its display case broken into by at least one perpetrator who was holding what appears to be a mallet.

According to one report on Twitter, the display case contained two pairs of diamond and sapphire earrings worth more than $10 million. Artnet News has reached out to TEFAF and the gallery to confirm what the items were, but did not hear back by publishing time.

According to Aachener Nachrichten, the thieves threatened employees while working to crack the case, which was set into the wall. De Limburger reported that the four suspects then fled the scene in a gray car with a foreign registration number before it was reportedly stopped on a local highway. Artnet News tried to contact the Limburg police for further clarification about the sequence of events and whether the objects were retrieved. 

One nearby stand told Artnet News, “my colleagues are in shock but we will continue with the fair. We are all safe which is the most important thing.”

“TEFAF has robust procedures in the event of a security breach,” said a spokesperson for the fair. “TEFAF and the MECC are now working with the authorities– no further statement will be made.”

The gallery Symbolic & Chase, which is located on Old Bond Street, has brought a variety of precious jewels to the fair, including a portrait-cut diamond ring designed by Greek jeweler Theodoros and brilliant cut sapphire earrings by Cartier. The fair, which has more than 200 exhibitors, runs until June 30.

Update July 4: This article was revised to include new information. The fair was not evacuated and the suspects were not disarmed.