European Union President Herman Van Rompuy on Sunday hailed the "courage" shown by Iran and world powers in their deal to curb Tehran's nuclear programme, but said the key lay in its "punctual" implementation. "It is now crucial to ensure punctual implemtation of the agreement reached and to continue working, on the basis of the trust that is being built, towards a definitive settlement of this issue," Van Rompuy said of the agreement which offers in exchange limited sanctions relief.