Iran says its potential retaliation against Israel for the killing of Hamas leader Ismail Haniyeh will be "unpredictable", while an analyst points to varied actions.

"For the time being, (Israel) must remain in a state of anxiety and panic as it awaits our revenge, but what is certain is that the response will be unpredictable," Iran's Deputy Defense Minister Seyed Hojatollah Ghoreishi was quoted by Iran's Tasnim News Agency as saying on Tuesday.

Reacting to the killing of Haniyeh on July 31 in Teheran, high-ranking Iranian officials have vowed to give a strong response, with Supreme Leader Ayatollah Ali Khamenei saying that Israel has prepared the ground for harsh punishment for itself through the assassination, Mehr News Agency reported.

On Tuesday, in a video broadcast on state television, Khamenei indicated that there was "no barrier" to discussions with the "enemy", possibly about civil use of nuclear energy and economic sanctions.

It is the US administration led by Donald Trump that pulled out of the Joint Comprehensive Plan of Action, which was signed in July 2015 and limits Iran's nuclear development.

The United States also reintroduced more sanctions against Iran. Such sanctions, among others, have made it difficult for Iran to purchase medicine and health supplies from abroad, including COVID-19 vaccines.

White House national security spokesman John Kirby said on Tuesday the US remains committed to defending Israel in the event of a possible Iranian attack.

Kirby told Israel's Channel 12 that it was tough to predict the chances of an attack but the White House takes Iranian rhetoric seriously.

"We believe that they are still postured and poised to launch an attack should they want to do that, which is why we have that enhanced force posture in the region," he said.

"Our messaging to Iran is consistent, has been and will stay consistent. One, don't do it. There's no reason to escalate this. There's no reason to potentially start some sort of all-out regional war. And number two, we are going to be prepared to defend Israel if it comes to that."

Some other US officials are also constantly issuing statements about potential retaliatory strikes on Israeli targets over the violation of Iranian sovereignty.

Patrick Ryder, spokesman for the US Department of Defense, said on Monday that the Pentagon continues to assess that there is a threat of attack by Iran and resistance groups against Israel.

Possible actions

Nagapushpa Devendra, a West Asia analyst and research scholar at the University of Erfurt in Germany, told China Daily that Iran may undertake "direct but more indirect" retaliatory actions against Israel.

Iran's actions may include supporting or encouraging proxy groups such as Hezbollah in Lebanon or other military forces in the region to launch attack on Israeli targets, Devendra said. Iran might also engage in cyber operations or other asymmetric tactics in response to the killing of Haniyeh, she said.

Regarding the reason for Iran's potential actions, she said: "Under the leadership of Iran's newly elected president, Iran is attempting to regain its security influence and capabilities that were undermined by sanctions imposed by the US.Given this scenario, it is likely that Iran's response may also be a way to assert its position as a key player in regional politics."

Agencies contributed to this story.