The rebuilding of the World Trade Center in the US following the 11 September 2001 terrorist attacks has lagged due to political, financial and architectural issues.

Only one of the five towers, the 2.6-million-square-foot Freedom Tower, now called One World Trade Center, planned for the Ground Zero site has broken ground, with the frame for the 1,776ft tower now reaching six-storey level.

The towers will replace over 11 million square feet of office space lost when the World Trade Center was destroyed by two passenger jets hijacked by al-Qaeda terrorists which hit the buildings killing 2,752 people.

The development plans include a public plaza, memorial, an underground museum, transit hub, retail complex and a performing arts centre at the 16-acre site Ground Zero site.

The battle between site owner Port Authority of New York and New Jersey and private developer Larry Silverstein, who leased the office space for 99 years is hampering the development of the site, according to US press reports.

The other three skyscrapers with 6.2 million square feet of office space that Silverstein is entrusted to build are embroiled in Silverstein war with the agency.