Iran said there had been “major progress” in all-night discussions with the U.S. into Monday, as the warring sides try to reach a peace deal within two months.

The countries began technical talks in the Swiss resort of Burgenstock over the weekend, following their interim agreement last week that led to a ceasefire extension and Iran reopening the Strait of Hormuz.

Plenty of obstacles remain, however, including Israel’s war in Lebanon against Hezbollah, an Iran-backed militant group. At one stage on Sunday, Iran said it would suspend talks — but never actually did — after U.S. President Donald Trump threatened military action against the Islamic Republic over its funding of proxy groups in the Middle East.