U.S. Federal Reserve Chairman Alan Greenspan will return to the United States from Switzerland on Wednesday, an official at the Bank for International Settlements (BIS) said. 

``He will be back in the United States today,'' a BIS spokeswoman told Reuters. No further information on Greenspan's travel plans was immediately available. 

All commercial U.S.-bound flights from Switzerland were canceled on Wednesday until at least later in the day. 

There was no word on whether New York Fed President William McDonough, who also was in Basel on Tuesday, would return with Greenspan. 

Both were in Switzerland on Monday to attend a regular meeting of central bankers at the BIS, and had been expected to leave on Tuesday. But Greenspan's flight was turned back after a series of terror attacks on public landmarks in the United States. 

A spokesman for Basel city police said he had no information on Greenspan's whereabouts on Wednesday. ``Even if I knew I couldn't tell you,'' said spokesman Klaus Mannhart.