According to Nasrallah, "The decision has been taken to respond, and the response will be very great."
"If Israel targets Iran, America bears responsibility," said the Hezbollah leader.
At the same time, Nasrallah denied that Hezbollah has, or would ever use, chemical weapons against Israel, but he stressed that Hezbollah has rockets that could hit Israel's "weak points," including economic, industrial, electrical, chemical and nuclear sites.
Meanwhile, the Israeli daily Yedioth Ahronoth accused the U.S. of secretly negotiating with Tehran to keep them out of a future Israel-Iran war.
According to the paper, the U.S. administration has sent a message to the Iranian officials via European mediators, stating that the U.S. would not support Israel if it decides to launch a military campaign against Tehran.
In return, the U.S. asked Iran to avoid attacking American bases in the region in any retaliatory action it might take against Israel, the newspaper reported, without mentioning sources of these news.
In response, White House spokesperson Jay Carney has officially denied having held secret talks with Iran.
“The report is false and completely incorrect,” said Carney. “And we don't talk about hypotheticals,” he added.
Moreover, the French Foreign Minister Laurent Fabius warned against an Israeli strike in Iran.
"I am absolutely opposed to the idea that Iran would gain nuclear weapons, but I think if there was an Israeli attack, unfortunately it would turn against Israel and would put Iran as the victim," said Fabius.
He also said, "Paris is concerned that, if there is a strike against them, they would be victimized and recover legitimacy among the population there. We say that we must increase sanctions and at the same time continue to discuss with Iran," he said.
"Unfortunately, the Chinese, Russians and Indians do not comply with the sanctions, it's a hole, even if sanctions are beginning to be more effective," he added.
Earlier, Reuters reported that the U.N.'s International Atomic Energy Agency (IAEA) says that Iran has increased its uranium enrichment capacity by at least 30 percent in the last four months and has doubled production capacity at the Fordo nuclear site.
The quarterly report of the IAEA on Iran states that some buildings were destroyed and earthworks were carried out in the military site as experts from agency wanted to inspect it. According to the report, Iran has 2,140 centrifuges at Fordo against 1,064 in May, but the new centrifuges are yet to be operational.
In its report, the IAEA has also accused Iran of having carried out activities at Parchin site that hinder significantly the ability of the agency to carry out effective inspections, stressing that Tehran has removed suspicious traces.
The Iranian Foreign Minister Ali Akbar Salehi has denied these accusations saying: "These statements have no technical basis. Experts know that they are mere pretexts and that we can not clean even one site".