Work on the foundations of an 838-metre skyscraper in China which will be the world’s tallest building has started, its constructor said Monday, adding the tower would be completed by April.

Rising from a field in the central Chinese city of Changsha, the “Sky City” tower broke ground on Saturday, builder Broad Group said in a statement sent to AFP.

A banner displayed at the site shows the top of the blocky tower 838 metres (2,749 feet) above the ground, a little above the current record-holder, the 830-metre Burj Khalifa in Dubai. The building’s construction will take just four months once the foundations are laid and cost nine billion yuan ($1.5 billion), the statement said. Such a construction speed has raised concerns over safety, in a country where infrastructure failures have caused disasters in the past.

The tower will boast a 10 kilometre long walkway stretching from the ground to the 170th floor, the group says, as well as a cinema, park and a children’s playground. Previous reports have said the building is designed to withstand a 9.0 level earthquake.