India on Friday voiced "serious concern" over what it termed a military nexus between its neighbours China and Pakistan, warning that New Delhi would try and match Beijing's growing firepower. Defence Minister A.K. Antony said India hoped to improve fractious relations with regional countries but that it must remain vigilant about ties between Pakistan and China. "The increasing nexus between China and Pak in the military sphere remains an area of serious concern," Antony told a seminar in New Delhi. "We have to carry out continuous appraisals of Chinese military capabilities and shape our responses accordingly." In the latest cross-border spat, China recently conveyed its "strong dissatisfaction" over the Dalai Lama's trip to the northeastern Indian state of Arunachal Pradesh which is claimed in full by Beijing. Antony repeated Indian criticism of arch-rival Pakistan, accusing it of failing to take responsibility for the attacks in Mumbai last year that left 166 people dead.