In response to recent speculation over an attack on Iran Hezbollah's Secretary General Seyyed Hassan Nasrallah has (according to Breaking News from Press TV) stated such an attack will ignite a full scale Middle Eastern war.
Hezbollah has boasted that its military capacity, in particularly its missile arsenal has been increased substantially since their last war with Israel in 2006. And given Hezbollah's reliance of Tehran and Damascus for arms one doubts it would remain passive if their main supplier were to go to war.
Update: Nasrallah has stated among other things, the following quote:
“The [US] must understand that war on Iran and Syria will not remain [restricted] in these two countries but will spread to other countries in the region. We are not issuing any threats but this is the reality."
“The era of weakness and [submission] to the US or Israel is over. We have entered the era of victories."
He made these statements at a 'Martyrs Day' event, an annual event that pays homage to past Hezbollah suicide bombers and insurgents who fought the Israelis from 1982 to 2000.