The Indian army said on Tuesday that 20 of its soldiers were killed in clashes with Chinese troops at a disputed border site, in a major escalation of a weeks-long standoff in the western Himalayas.

In a statement, the army said that 17 critically injured Indian troops succumbed to their wounds, in addition to an officer and two soldiers who had died earlier.

Indian and Chinese troops have disengaged in the areas where the clashes took place, the statement said.

Beijing on Tuesday confirmed the incident and accused India of crossing the border and “attacking Chinese personnel”.

Chinese foreign ministry spokesman Zhao Lijian said Indian troops “crossed the border line twice… provoking and attacking Chinese personnel, resulting in serious physical confrontation between border forces on the two sides.”

Indian officials say the latest row began in early May, when Chinese soldiers entered the disputed territory of Ladakh at three different points, erecting tents and guard posts. They said the Chinese soldiers ignored repeated verbal warnings to depart, triggering shouting matches, stone-throwing and fistfights. China has sought to downplay the confrontation while providing little information.