As the possibility of a challenge increases, Umno Youth chief Hishamuddin Hussein has been warned to be cautious of 'enemies' within the wing who may take advantage of the situation.

"Unfortunately, there are indications that such a thing could be happening...so he must be aware of them...," said a party source who declined to be named today.

He said the recent statement by Umno information chief Megat Junid Megat Ayob that only the president and deputy president post would not be contested has opened the Pandora's box.