Jerusalem, Sep 18 : The Israel Defense Forces (IDF) was braced for a response after Hezbollah accused Israel of being behind a wave of exploding pagers that killed at least nine and injured thousands.

Lieutenant General Herzi Halevi, the IDF's Chief of Staff, on Tuesday, insisted Israel remains ready "for attack and defence in all arenas" without mentioning the pager attacks which occurred across Lebanon and in parts of Syria.

"We will update immediately on any change to (Home Front Command guidelines)," the IDF added.

Lebanon and Hezbollah have both accused Tel Aviv of being behind the attack, with the Lebanese Prime Minister labelling it as "criminal Israeli aggression" and a "serious violation of Lebanese sovereignty".

Hezbollah, whose fighters were injured and killed in the attack, also said it holds the "Israeli enemy fully responsible for this criminal aggression".

"This treacherous and criminal enemy will certainly receive its just punishment for this sinful aggression," they said in a statement.

The US said it was investigating the attacks and denied claims made in Iranian media that it had advanced knowledge of the explosions.

"The US was not aware of this incident in advance and, at this point, we're gathering information," the State Department said.

The White House has urged restraint from Hezbollah and Iran, whose ambassador to Beirut, was hurt in the attack.

The Foreign Office has called for "calm heads and de-escalation" after hundreds of pagers exploded simultaneously across Lebanon in what appeared to be a coordinated attack.

An FCDO spokesperson said: "We continue to monitor the situation in Lebanon closely and the UK is working with diplomatic and humanitarian partners in the region. The civilian casualties following these explosions are deeply distressing."

"We urge calm heads and de-escalation at this critical time."

/IANS