NEW DELHI, May 26 (AFP) - India's ruling Hindu nationalists Wednesday accused Pakistan of turning Kashmir into a "war zone" by sending Moslem mercenaries into the Himalayan state. "The Indian army will give them a befitting reply," a spokesman for Prime Minister Atal Behari Vajpayee's BJP party said. The spokesman's comments came after the Indian air force bombed Moslem separatists who have taken control of key hills along the Kashmir border after infiltrating from Pakistan. The military strikes have sparked tensions between India and Pakistan. India's main opposition Congress party said the fighting in Kashmir marked the diplomatic failure of the Hindu nationalists' attempts to improve relations with Pakistan. "The situation (on the border) is extremely serious," Congress spokesman Natwar Singh told reporters. Vajpayee undertook a historic bus journey to Pakistan in February for peace talks with his Pakistani counterpart Nawaz Sharif. That meeting was supposed to be the dawn of a detente in India-Pakistan ties, particularly over Kashmir, a Himalayan region whose ownership is disputed by both countries.  