Tesla welcomes the public at an open day held at Berlin 'gigafactory'

Thousands of people are expected to head to Tesla's new factory on the outskirts of Berlin on Saturday as the electric carmaker's chief executive Elon Musk hosts a "county fair."

Hundreds of people had reached the site by midday, eager to explore Tesla's first European factory in Gruenheide.

Tesla hopes its vehicles will start rolling off the assembly line by the end of the year, with the ultimate aim of producing 500,000 electric cars annually.

Musk confirmed he planned to attend the event and landed in the city on Friday.

Other attractions included a Ferris wheel, food trucks and DJs.

Tesla encouraged people to travel to the event by train, while police were preparing for traffic delays.

Visitors had to make advance reservations for the tickets which were greatly in demand.

The factory for the construction of electric vehicles is one of the most important industrial projects to be established in Germany's east for years.

Tesla hopes the plant may start operations this year despite the fact that it has yet to be granted final environmental approval by the state of Brandenburg.

As the approval is considered likely, the company is continuing to expand the plant.

Nonetheless, locals and activists fear the construction could harm drinking water and have a negative impact on the environmental surroundings.

In order to hold the open day, Tesla obtained permits allowing up to 9,000 attendees to attend and to be able to host the event even though the site is located in a protected area.