India has no right to carry out development in the area China calls South Tibet, China’s Foreign Ministry said on Wednesday in response to a Reuters report on New Delhi’s plans to speed up hydropower projects in the border state.

“South Tibet is China’s territory,” a foreign ministry spokesman said in a statement.

It said India had no right to carry out development there and the establishment of what India calls Arunachal Pradesh on Chinese territory is “illegal and invalid”.

Reuters reported on Tuesday that India plans to spend $1 billion to expedite the construction of 12 hydropower stations in the northeastern Himalayan state.

India’s Foreign Ministry did not immediately respond to a request for comment on China’s statement.

India says its remote state of Arunachal Pradesh is an integral part of the country, but China says it is a part of southern Tibet and has objected to Indian infrastructure projects there.

Last week, India Foreign Minister Subrahmanyam Jaishankar met his Chinese counterpart Wang Yi in Kazakhstan where the two agreed to intensify efforts to resolve issues along their border.