France, April 12 -- Vance said Washington was seeking a "fundamental commitment" from Iran not to develop a nuclear weapon, adding that "we haven't seen that" after the highest-level talks between the two sides since the 1979 Islamic Revolution.

However, he signalled the United States was still giving Tehran time to consider its proposal, after announcing on Tuesday a two-week pause in joint attacks with Israel to allow space for negotiations.

Pakistan, which hosted the talks and helped bring the rivals to the table, said it would continue facilitating dialogue and urged both sides to respect the temporary truce.

Iran's state broadcaster IRIB said negotiations stalled over "unreasonable demands" from the US, though the foreign ministry...