"The UAE embassy had sought clearance for over flying and landing of their air force flight at [Calcutta] Airport en route to Xinjiang, China," the Indian Foreign Ministry said.

Xinjiang is the Chinese province in which bloody clashes took place in August 2009. The regional capital, Urumqi, is populated mainly by Turkish-speaking Muslims called Uighurs.

This marked the first time the UAE was found to have transported weapons to China. Abu Dhabi has been regarded as a major ally of Pakistan, a leading defense client of Beijing.

"The operator had written that they are not carrying arms and ammunition," Indian Air Force spokesman Wing Cmdr. Mahesh Upasani said.

Upasani, in an interview with Indian television, did not identify the weapons and ammunition aboard the UAE aircraft. He said the 10-member UAE Air Force crew had been taken for questioning and the plane was still being held on Sept. 9.

The UAE has acknowledged that its military transport was stopped in Calcutta. But a UAE Foreign Ministry statement on late Sept. 7 did not cite the finding of weapons along the air force plane.

"We reaffirm the UAE respect for Indian sovereignty," the UAE Foreign Ministry said in a statement.

India and Pakistan have been wooing the UAE and other Gulf Cooperation Council states with military cooperation and arms sales. Pakistan has been staging regular military exercises with several GCC states, including Qatar, Saudi Arabia and the UAE.