Organisers hailed the opening of Expo Milan 2015 as a success, as the number of people who visited the world fair exceeded expectations of hundreds of thousands.

Up to 650,000 people toured the 1.1 million sq m exhibition area on the outskirts of the northern Italian city in the first three days since it opened its gates on 1 May, according to Coldiretti Italys main farmers union, which has a dedicated space at Expo.

The first weekend went beyond expectations, Expo chief Giuseppe Sala told a press conference.

The gastronomy-themed Universal Exhibition was initially projected to attract 200,000 people for the opening weekend, while 220,000 reportedly showed up on the first day only.

These are record figures that make us enthusiastic, Milans mayor Giuliano Pisapia was quoted as saying by Ansa news agency.

Organisers triumphant tones were not diminished by the violent anti-Expo protests that engulfed Milans city centre on May Day, marring the fairs inauguration, or by construction delays triggered by a corruption investigation that affected the early stages of preparations.

Numerous exhibition areas are yet to be completed and workers could be seen at the site finishing off some pavilions amid crowds of tourists.

Food focus aims to feed the Italian economy

With Feeding the Planet, Energy for Life as the central theme, the Milan Expo is focused on food. Coldiretti estimated some 800,000 meals were consumed and paid for at the many restaurants and foot stands on site over the first three days of the exhibition.

The encouraging numbers further fuelled hopes the event will work as a driving force to pull Milan and the rest of the country out of its economic quagmire.

In December 2014, Sala said they hoped the fair would generated a €10bn (£7bn, $11bn) return for the country in terms of GDP.

Days before the inauguration, Prime Minister Matteo Renzi said 10 million tickets, with a standard price of €39 had already been sold. Around 20 million people are expected to visit site over a six-month period.

Some 145 countries, from the tiny Holy See to the US and China, are taking part in the event, showcasing their best delicacies and innovative ways of producing them, in purpose-built pavilions with futuristic architectures. Expo Milan 2015 runs until October.