The Washington Post claims that US Defence Secretary Leon Panetta believes there is a growing possibility that Israel will attack Iran as early as April.
An opinion article published on Thursday says the strike is likely to happen either in April, May, or June.
Panetta and the Pentagon both declined to comment on the report.
In Israel too, the Iran rhetoric has been stepped up, with a warning that time is running out to stop Tehran developing a nuclear weapon.
Israeli officials say Iran is developing a weapon that can reach the US, while Iran maintains its nuclear programme is for civilian purposes.
Al Jazeera's Nicole Johnston reports.
