The leader of the Lebanese Shiite militant Hezbollah says his group will transform the lives of millions of Israelis to "hell" if Israel attacks Lebanon.
Sheikh Hassan Nasrallah says the group has a list of Israeli targets that it can hit with few rockets.
"We can transform the lives of millions of Zionists in occupied Palestine to a real hell," he said.
The threat came as Israel debated whether to attack Iranian nuclear facilities. That could trigger retaliation from Iran's allies, like Hezbollah.
Nasrallah said Iran's response to any Israeli attack would be "lightning" and huge.
Nasrallah spoke in a televised speech marking Jerusalem Day on Friday.
Israel and Hezbollah fought a deadly, inconclusive monthlong war in 2006, when Hezbollah fired about 4,000 rockets at Israel.