Washington: Issuing a fresh warning to Syria and Iran, US President George Bush has accused both the countries of supporting and harbouring terrorism and said "their behaviour is completely unacceptable".

"States that support terror will be held accountable," Bush said at his ranch in Crawford, Texas, on July 22 while welcoming Italian Prime Minister Silvio Berlusconi.

He said it was time for all governments in the Middle East to support Israel and the Palestinians as they strive to end their conflict.

"This includes the governments of Syria and Iran," he said adding "Today, Syria and Iran continue to harbour and assist terrorism. This behaviour is completely unacceptable."

Bush added that states which he said support terrorism will be "held accountable" and that terrorism undermined the prospects for Middle East peace.

"Terrorism is the greatest obstacle to the emergence of a Palestinian state and all leaders who seek this goal have an obligation to back up their words and real actions against terror," he said.

PTI