Hezbollah leader Sayyed Hassan Nasrallah said on Friday Saudi Arabia had declared war on Lebanon and Hezbollah, and said Lebanese Prime Minister Saad Hariri, who resigned in a speech from Riyadh on Saturday, was being detained in Saudi.

In a televised address Mr Nasrallah said Mr Hariri's resignation was an "unprecedented Saudi intervention" in Lebanese politics and called for Mr Hariri to return to Lebanon.

He said Lebanon's government was still legitimate and had not resigned.

Mr Nasrallah said war with Israel was unlikely amid the crisis facing his country. He said his powerful militant group is watching carefully for any Israeli attempts to use the crisis to begin hostilities against Lebanon.

Mr Nasrallah said Israel was cautious and unlikely to make such a move.

Mr Nasrallah is calming an apparently jittery population following Saudi Arabia's escalation against Hezbollah's patron Iran.

The resignation of Prime Minister Saad Hariri from Saudi Arabia last week was seen as a move by Riyadh to take its rivalry with Iran to the tiny Lebanon.

Lebanese Prime Minister Saad Hariri resigns

Many fear the escalation will pave the way for Israel to strike against Hezbollah, against which Israel has fought a number of wars. Mr Nasrallah warned Israel against "miscalculation" or "taking advantage of the situation."

He said Israel should not think "we are troubled. No, absolutely not."