Milan Expo 2015 has cleared the final hurdle to registration at next month's general assembly of the Bureau of International Expositions (BIE), Milan authorities announced here.

"We got green lights for the recording," special commissioner for the Expo and mayor of Milan Letizia Moratti said at a press conference, referring to notification that it had won BIE's official recommendation for registration as the next World Expo.

Of the 155 BIE member states, six (France, Germany, Denmark, Finland, Canada and Japan) had submitted requests for clarification, some about the availability of the Expo areas. These were resolved last week when two major landowners reached an agreement with the Milan municipality.

"We answered all the questions and made a very detailed presentation," Moratti said, adding that, after the formal registration, the Presidency of the Council will send invitation letters to BIE's countries and begin negotiations with those interested in participating in Milan Expo.

"The important thing now is to agree on those contractual relationships that we built on an informal basis," said Giuseppe Sala, Expo 2015 chief executive, adding that it would be a difficult challenge to make an innovative Expo, from the construction of buildings to technology and content.

"Next week our delegation will go to Shanghai, which is hosting Expo 2010, for the takeover celebrations," Lombardy region governor Roberto Formigoni told Xinhua at the press conference.

"We are paying maximum attention to the extraordinary Expo organized by our Chinese friends in Shanghai, and we aim to learn from their optimum solutions," he said.