THE US-IRAN truce threatened to collapse today after the US bombed Iranian boats and ports and Iran said it shot down a US Reaper drone in retaliation.Though talks continued, yesterday through the mediation of Qatar, on a peace deal Iranian officials briefed that the bombings showed they were right to have “zero trust” in the US.Washington said it bombed ships in “self-defence” and accused them of laying mines. It added that attacks in defence of its “assets” didn’t count as ceasefire violations.