BEIRUT (Reuters) - Hezbollah leader Sayyed Hassan Nasrallah said on Friday Saudi Arabia had declared war on Lebanon and Hezbollah, and said Lebanese Prime Minister Saad al-Hariri, who resigned in a speech from Riyadh on Saturday, was being detained in Saudi.  In a televised address Nasrallah said Hariri s resignation was an  unprecedented Saudi intervention  in Lebanese politics and called for Hariri to return to Lebanon. He said Lebanon s government was still legitimate and had not resigned.  