Switzerland has frozen assets held in the country by Venezuela's Nicolas Maduro and associates, the Swiss government said on Monday, following his arrest by U.S. forces in Caracas and transfer to the United States.

A spokesperson for the Swiss Foreign Ministry said the order affects 37 people. The spokesperson said the ministry could not provide any details on the value of the assets in question.

The measure, effective immediately and valid for four years, aims to prevent an outflow of potentially illicit assets and comes in addition to existing sanctions imposed on Venezuela since 2018, the government said in a statement.

The asset freeze does not affect members of the current Venezuelan government, and Switzerland said it will seek to return any funds found to be illicitly acquired to benefit the Venezuelan people.

The government said the situation in Venezuela was volatile, with various outcomes possible in the coming days and weeks.

It said it was following the situation closely, and called for de-escalation and restraint, while also offering its good offices to find a peaceful solution.

"The Federal Council wants to ensure that any illicitly acquired assets cannot be transferred out of Switzerland in the current situation," it said.

The asset freeze was a precautionary measure and applied to Maduro and his associates as foreign politically exposed persons, the government said.