US secretary of state Mike Pompeo has threatened Iran with “the strongest sanctions in history” as he issued demands that he said should be included in a nuclear treaty with Iran to replace the Obama-era deal.

Following US president Donald Trump’s withdrawal from the 2015 deal, America will ensure “Iran has no possible path to a nuclear weapon, ever”, Pompeo said.

As he called for a better agreement to constrain Iran’s activities, he said the US would “apply unprecedented financial pressure” to bring Tehran back to the table.

“These will end up being the strongest sanctions in history by the time we are complete,” Pompeo said at the conservative Heritage Foundation, in his first major policy speech since taking over as the top US diplomat.

Pompeo’s list of 12 requirements included many that Iran is highly unlikely to consider.

He said Iran must “stop enrichment” of uranium, which was allowed within strict limitations under the 2015 deal.

Iran must also allow nuclear “unqualified access to all sites throughout the country”, Pompeo said, alluding to military sites that were off-limits under the 2015 deal except under specific circumstances.

To that end, he also said Iran must declare all previous efforts to build a nuclear weapon, reopening an issue that the UN’s International Atomic Energy Agency has already deemed a closed matter.