NEW DELHI, Oct 10: In an apparent effort to derail a crucial visit to Beijing by Congress Party leader Sonia Gandhi, Tibetan protesters raided the Chinese embassy in New Delhi on Wednesday while two other seemingly unrelated events cast a shadow on Sino-Indian ties.

A joint military exercise with India was postponed indefinitely by Beijing, and Chinese troops engaged in a dispute with their Indian counterparts over a border post in Sikkim, referred the matter to their foreign ministry.

For the Chinese though, a Tibetan demonstration is usually the more serious matter. A handful of Tibetan activists broke through the gates of the Chinese embassy in Delhi, just across the road from the heavily guarded US embassy, and painted “Free Tibet” on the building walls before being arrested by police.

The demonstrators were nabbed by the embassy guards and then pushed out of the building.

Ms Gandhi is expected to visit Beijing this month at the invitation of President Hu Jintao.

Meanwhile, China and India have indefinitely postponed their first joint military exercise, Indian news agencies reported. The exercise was to be held in China next month.

According to one version of the Sikkim “incident”, some Chinese soldiers had asked the Indian side to vacate two bunkers about six-seven weeks ago. But, the Indian soldiers refused to do so. Then, the soldiers said that they would take up the issue through a diplomatic channel.

On Wednesday, PTI quoted Chinese spokesperson Liu Jianchao as claiming that India had built “facilities” on its side of the Sikkim border in “violation” of the bilateral agreement on maintaining peace in the region.