Morristown, New Jersey - President Donald Trump said Friday that Iran had a "maximum" of two weeks to avoid possible US air strikes, indicating he could make a decision before the fortnight deadline he set a day earlier.

Trump added that Iran "doesn't want to talk to Europe," dismissing the chance of success in talks between European powers and Iran in Geneva on resolving the conflict between Israel and Iran.

Trump also played down the possibility of asking Israel to halt its attacks, after Iranian Foreign Minister Abbas Araghchi said Tehran would not resume talks with the US until Israel relented.

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"I'm giving them a period of time, and I would say two weeks would be the maximum," Trump told reporters when asked if he could decide to strike Iran before that.

He added that the aim was to "see whether or not people come to their senses."

Trump had said in a statement on Thursday that he would "make my decision whether or not to go within the next two weeks" because there was a "substantial chance of negotiations" with Iran.

Those comments had been widely seen as opening a two-week window for negotiations to end the war between Israel and Iran, with the European powers rushing to talks with Tehran.

Trump dismissed the chances of Europe making a difference, saying the talks between Britain, France, Germany, and EU diplomats and Tehran's foreign minister "didn't help."

"Iran doesn't want to speak to Europe. They want to speak to us. Europe is not going to be able to help in this," Trump told reporters as he arrived in Morristown, New Jersey.

Asked if he would ask Israel to stop its attacks as Iran had asked, Trump said it was "very hard to make that request right now."

"If somebody's winning, it's a little bit harder to do than if somebody's losing, but we're ready, willing, and able, and we've been speaking to Iran, and we'll see what happens."