Kohn Pedersen Fox, the New York-based architects, said on Wednesday that they had completed designs for the world’s second biggest skyscraper, to be built in Seoul by Lotte, the South Korean conglomerate.

James von Klemperer, leading the design team, said Lotte had set “an aggressive schedule” to complete the 555m-high building by 2014 and that the digging works for the foundations had been carried out.