GENEVA (Reuters) - A Swiss armored van was held up by masked men holding the daughter of one of the security guards hostage in France, Vaud cantonal police said on Friday, as a French police source told Reuters that the loot could be up to 26 million euros.

The 22-year-old daughter was released after the heist on Thursday night, but the three men escaped in a luxury sport utility vehicle from a parking lot at Chavornay, located north of Lausanne, where the van had been forced to park before being emptied, Vaud cantonal police said.

“The thieves fled to an unknown destination. The daughter of one of the security guards was held hostage in France but then released. There were no injuries,” it said in a statement that gave no estimated value of the amount stolen.

A French police source, confirming a report on French radio Europe 1, told Reuters in Lyon, France that the armored van was believed to be carrying 15 to 30 million Swiss francs (13-26 million euros) in cash.

Europe 1 reported that the woman had been held hostage by men pretending to be plumbers at her home in Lyon, France.

Twelve Swiss police patrol cars and investigators were deployed in the operation and a criminal case has been opened, the Vaud police statement said, appealing for witnesses.