U.S. President Trump will never start a war with Iran during an election year, Iranian President Hassan Rouhani said.

Rouhani told a Tehran news conference Sunday that Trump knows a war between Iran and the United States would "ruin" his chances of reelection in November.

"I think the Americans aren't after war since they know what harm it could do them," he said.

The level of hostility between the United States and Iran has been increasing steadily and has reached a level not seen since the hostage crisis 40 years ago.

Among the events contributing to the hostility are Trump's decision to pull the U.S. out of the international nuclear deal with Iran in 2018 and reimposed sanctions. Iran responded by backing away from the deal and saying it is no longer bound by the limits on uranium enrichment spelled out in the agreement. Britain, France and Germany are struggling to keep the deal from complete collapse.

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In January, Trump ordered a U.S. drone strike that killed Iranian General Qassem Soleimani and Iraqi militia leader Abu Mahdi al-Muhandis. Iran responded with a missile strike on an Iraqi base that houses U.S. coalition troops. Nearly 100 U.S. soldiers were injured in the attack.

The U.S. consistently accuses Iran of terrorism, and Iran says U.S. imperialism is destroying its economy and fueling conflicts in the Middle East.

But both sides have so far avoided all-out war.

Rouhani said Sunday Iran would never negotiate with the United States under pressure, but invited the U.S. to rejoin the nuclear agreement. He said it will be Iran that will one day force the U.S. to return to the negotiation table.

"Iran will never negotiate under pressure. ... We will never yield to America's pressure and we will not negotiate from a position of weakness," Rouhani said.

The Iranian president also said that Tehran's role was essential for security in the region.

"Securing peace and stability in the sensitive region of the Middle East and in the Persian Gulf is impossible without Iran's help," he said.