MONTREUX, Switzerland - The US and Iranian foreign ministers wrapped up three days of talks over Iran's nuclear program on Wednesday, a day after Israeli Prime Minister Benjamin Netanyahu said the deal being negotiated was a serious mistake.US Secretary of State John Kerry and Iran's Mohammad Javad Zarif have negotiated for more than 10 hours since Monday in the Swiss lakeside town of Montreux, hoping to work out a framework deal by late March."We have made some progress but have a lot of challenges yet ahead," a senior US State Department official told reporters traveling with Kerry."The bottom line here is that (there is) no deal to announce to anybody today, but very intense, hard work, some progress, but tough challenges yet to be resolved," the official said."We expect that we (and the Iranians) will regroup bilaterally, with the European Union present as well, on the 15th of March, location to be confirmed but most likely Geneva."Asked if he thought they had made progress, Zarif told reporters: "We have, but a lot of work remains."However, Netanyahu's controversial speech to the US Congress on Tuesday, where he harshly criticized the diplomatic efforts to resolve the dispute, may make it harder for the Obama administration to sell the potential deal back home.US negotiator Wendy Sherman will brief Israel soon on the talks and Kerry will meet the foreign ministers of Britain, France and Germany in Paris on Saturday, the senior US official said.