NEW YORK CITY (AFP) - The wife of US Secretary of State John Kerry was on Sunday rushed to hospital after falling ill, a US source told AFP.

Mrs Teresa Heinz Kerry "suffered some kind of medical episode" and was taken to a local hospital in Nantucket, a source close to Kerry said.

Mrs Heinz Kerry, a multilingual philanthropist born to Portuguese parents in colonial-era Mozambique, was undergoing tests and Kerry was by her side, he added.

Mr Kerry had been celebrating the July 4 with his family at their home on Nantucket Island, Massachusetts on his first long break since he took over in February as the top US diplomat.

He and his wife, 74, have been married for some 18 years. It is a second marriage for both of them.

Mr Kerry has kept up a grueling schedule since becoming secretary of state and had been expected to travel back to the Middle East soon as he pursues a bid to relaunch negotiations.