The US secretary of state, Marco Rubio , has said that Washington is expecting a response from Iran on Friday to its proposals for an interim deal to end the conflict in the Middle East, as Iran accused the US of breaching the increasingly fragile ceasefire announced last month. In recent days there have been the biggest flare-ups in fighting in and around the contested strait of Hormuz since the informal truce began. The rise in violence followed Donald Trump’s announcement – then rapid pause – of a new naval mission aimed at opening the strategic waterway. On Friday US forces fired on and disabled two Iranian-flagged tankers that attempted to violate the American blockade of Iran’s ports, the US military said. Despite the clashes diplomatic efforts continue, with the mediators Pakistan passing to Iran a brief memorandum that the US has said could act as a basis for a more solid ceasefire allowing new talks.…