By Asif Shahzad, Alexander Cornwell and Ariba Shahid

ISLAMABAD/TEL AVIV, April 8 (Reuters) - Mediation efforts to halt the war in Iran were hours from collapse when Pakistan mounted an overnight diplomatic push to secure a temporary ceasefire and bring Washington and Tehran into direct negotiations, four Pakistani sources told Reuters.

The effort nearly unravelled after an Iranian strike on a Saudi petrochemical facility triggered fury in Riyadh and threatened to derail weeks of back-channel diplomacy, the sources - with direct knowledge of the talks - said.