Stockholm, Sep 16 (IANS): Danish brewing company Carlsberg recalled beer from hundreds of Swedish restaurants after customers detected a suspected corrosive substance.

Two guests began to bleed from their mouths after consuming beer that was assumed to contain a cleaning detergent, prompting Carlsberg to withdraw kegs from 680 restaurants on Tuesday, Xinhua news agency reported.

"It is not the case that all the beer contains detergent, but we are doing this as a precautionary measure," Carlsberg's Swedish head of communications Henric Bystrom said.

The recalled kegs came from a brewery in Prague that produces beer under the Czech brand Staropramen, the company said.

Carlsberg could not specify the extent of the dilution but said the affected beverages would not smell or taste like beer.

"Our indication is that this concerns a few kegs. What we are trying to find are dates and times at which this beer was brewed," Bystrom said.