Vienna, March 19 (IANS) The talks between Iran and six world powers in Vienna is "substantive and useful", a spokesperson for EU foreign policy chief Catherine Ashton said Tuesday. The comment was made after Tuesday's talks between Iran and the P5+1 group, namely Britain, China, France, Russia, the US plus Germany, heading to a comprehensive deal to resolve the long standing disputed Tehran's nuclear programme, Xinhua reported. "Plenary discussions today are substantive and useful," a spokesperson for Ashton said in an e-mail. Based on the progress made in the last round of talks between Iran and the P5+1 group last month, all parties involved in the talks, scheduled for Tuesday to Thursday in Vienna, are working on specific issues.