In 2003, with the thawing of Sino-Indian relations, Indian Prime Minister Atal Bihari Vajpayee's visit to China led to the resumption of talks on opening the border. Later in 2004, the Indian Defence Minister's visit to China led to the formal opening of the pass. The opening, originally scheduled for 2 October 2005, was postponed due to last-minute infrastructure problems on the Chinese side. Finally, after a decade of talks, Nathu La was opened on 6 July 2006. The reopening, which also signified the formal recognition of Tibet as part of China by India and Sikkim's accession to India by China, coincided with the birthday of the reigning Dalai Lama. In the years before the reopening, the only person permitted to cross the barbed-wire frontier had been a Chinese postman with an Indian military escort, who would hand over mail to his Indian counterpart in a building at the border.