India has freed up thousands of soldiers to strengthen its disputed border with China, adding a potential irritant to its already sour relations with Beijing.

A 10,000-strong unit of soldiers previously assigned to the country’s western border has now been set aside to guard a stretch of its frontier with China, said senior Indian officials who didn’t want to be named because discussions are private.

In addition, an existing contingent of 9,000 soldiers, already designated to the disputed Chinese border, will be brought under the newly created fighting command. The combined force will guard a 532-kilometer stretch of border that separates China’s Tibet region with India’s northern states of Uttarakhand and Himachal Pradesh.