Lausanne - The US abandoned late on Tuesday a midnight deadline to agree the outlines of a nuclear deal with Iran but insisted that "enough progress" merited extending marathon talks into Wednesday.
"We've made enough progress in the last days to merit staying until Wednesday. There are several difficult issues still remaining," State Department spokesperson Marie Harf said.
The announcement came late on a sixth day of talks in Switzerland aimed at laying the groundwork for a deal that world powers hope will prevent Iran developing nuclear weapons under the guise of its civilian programme.