New York – A tornado warning was issued for the New York area on Saturday as a severe thunderstorm capable of producing a twister moved over the area, dumping heavy rain to delay the start of play at the US Open.

The storm pushed back the scheduled start of British third seed and London Olympic champion Andy Murray's men's semi-final against Czech sixth seed Tomas Berdych at Arthur Ashe Stadium.

That match is set to be followed by the other semi-final, defending champion and Serbian second seed Novak Djokovic against Spanish fourth seed David Ferrer.

“Today' s daytime forecast calls for overcast skies with the potential of isolated showers and thunderstorms,” said a US Open official.

“In an effort to complete today' s day session, we plan to begin play as soon as courts are dried. We are monitoring the weather closely and will provide an update for today's evening session at noon ET (Eastern Time).”

In the night session, Serena Williams and Victoria Azarenka are scheduled to play the women's final. – Sapa-AFP