NEW : Syria President tweets on `` ` 1 hour of constructive & pragmatic dialogue '' NEW Leaders from Britain and Iran met Wednesday for the first time in 35 years , a potential breakthrough conversation that occurs at a time when Tehran is trying to shed Western-led sanctions over its nuclear program and Western nations are trying to garner international support for their campaign against ISIS . : He criticizes U.S.-led strikes in Syria , yet opens door to `` a new atmosphere '' with Iran NEW : Cameron : Despite `` severe disagreements , '' ISIS could help defeat Iranians . NEW : Prime Minister : If they can help , `` we should welcome their engagement ''
NEW : Syria President tweets on `` ` 1 hour of constructive & pragmatic dialogue '' NEW : He criticizes U.S.-led strikes in Syria , yet opens door to `` a new atmosphere '' with Iran NEW : Cameron : Despite `` severe disagreements , '' ISIS could help defeat Iranians . NEW : Prime Minister : If they can help , `` we should welcome their engagement ''