Inside the Trump administration, officials are expressing fears that Iran is in the “advanced stages” of planning attacks against United States (US) officials.

More than 6,000 miles away, the Iranians appear convinced that Israel and the United States are preparing to unleash their third major attack in 16 months, a final push to force Iran to surrender to US demands.

The conflict in West Asia has entered a new phase in which a maelstrom of factors, from the political calendars in the United States and Israel to the potential for all sides to be seeking pretexts for action, is creating heightened levels of tension and risk.

This is how countries can escalate into full-scale war, several diplomats and outside experts noted.

If the US intelligence disclosed this week is right that Iran has credible plans to attack Americans at home and abroad, one senior European official said — “and it probably is,” the official added — one gunshot that appears aimed at a US official could touch off a conflagration. So could a stray explosion near a bunker sheltering Iranian leaders, who already survived their predecessors’ deaths in a decapitation strike in the opening hours of the war on February 28.

The fact that Israeli Prime Minister Benjamin Netanyahu and President Trump are facing critical elections that could dramatically affect the balance of power in their countries feeds into the complex set of calculations that all sides are making.

Even if he is defeated on Tuesday, Netanyahu could decide to launch one last strike that he may believe his successor would hesitate to execute. Similarly, Trump, who knows how unpopular the war is even among his strongest supporters, may want to show that, at least when it comes to his powers as commander-in-chief, his authority is undiminished.

Still, those incidents are a reminder that US and Iranian fears are rooted in bitter experience. And while Trump has said he would not attack before the midterm elections in 10 days, he has also hinted that all bets are off after that. Senior US officials say that, in private, Trump appears to be leaning towards another round of major strikes inside Iran.

Plans developed by Central Command detail an expanded list of bombing targets, including energy infrastructure and other sites vital to the Iranian economy, according to an official with direct knowledge of the planning. Echoing Trump’s bombast, a senior official in Iran took to social media in recent days to say the country was preparing to take on its adversaries with surprise attacks, with “zero red lines”.

Trump said nothing to reporters on Saturday about the intelligence, but did say he would decide soon whether to take renewed military action. He has been briefed regularly on the new intelligence, which some officials say is being taken more seriously than any warnings since the war began.

Iranian officials believe their most inspired moves after the February 28 attack included striking US bases across West Asia and closing the Strait of Hormuz, which caught the US off guard. They have made no secret of their intentions to expand the scope of the war if a third round of fighting breaks out.

In public remarks, senior officials have threatened to target civilian infrastructure, energy sites and underwater fibre-optic cables that carry internet and other communications traffic. Two Iranian officials said in interviews that the expansion of targets also included US diplomats and personnel. The officials confirmed State Department reports about Iran’s plot to target Americans.