New Delhi, April 9 -- The 'fragile' ceasefire between Iran and the United States appeared to be weakening on Thursday, as Tehran threatened to resume hostilities while Israel continued heavy strikes in Lebanon.

Washington and Tehran both claimed 'victory' on Tuesday after agreeing to a ceasefire and to negotiations aimed at ending the Middle East conflict. But tensions escalated as Israel carried out deadly strikes in neighbouring Lebanon - including in densely populated central Beirut - in the biggest attack since the Iran-backed militant group Hezbollah joined the war in early March. At least 182 people were killed and nearly 900 wounded on Wednesday, the Lebanese Health Ministry said.

Hezbollah responded on Thursday, saying it had fi...