'I think you can forget about the Ryder Cup for a few months at least,' former British Open champion Mark Calcavecchia told Wednesday's Daily Express newspaper.
Stewart Cink told the paper he felt 'a lot less safe about flying to England than I did 24 hours ago. If someone wanted to strike at America, or freedom, or capitalism, the Ryder Cup would be a tempting event to hit.'
The 34th Ryder Cup matches are scheduled for September 28-30 at The Belfry in Sutton Coldfield, England.
Several European players, who were in St. Louis preparing for the American Express Championship,' expressed shock at what happened Tuesday.
'This is sick,' said Colin Montgomerie, a member of Europe's Ryder Cup team. 'I am totally shocked and I really don't know what to say. I don't think a movie would have come up with something like this. I don't think anything will be normal for a long time to come. It was not a fair fight. They did anything they wanted. It's just awful.'
The Ryder Cup, which began in 1927, was suspended during World War II, but has been held every two years since.
Full Coverage of the 34th Ryder Cup Matches