NEW DELHI - Prime Minister Manmohan Singh of India on Tuesday made what may be one of his most aggressive public statements about Pakistan, accusing the neighboring country of restarting hostilities in the disputed Kashmir region last week and saying the action had halted growing cooperation between the two.

"After this dastardly act, there can't be business as usual with Pakistan," Singh told local television station NDTV, referring to a recent episode in which India claims an Indian soldier was beheaded by Pakistani soldiers.

India and Pakistan have maintained a cease-fire since November 2003, and relations had been improving over the past year. But on Jan. 6, Pakistan accused the Indian army of crossing the "Line of Control," the disputed border the countries share, killing one Pakistani soldier and wounding another.

India denied the accusations and two days later accused Pakistan of killing two Indian soldiers at the line and of beheading one of them. Pakistan denied those charges.

India's external affairs minister, Salman Khurshid, echoed the prime minister's words in a statement issued later Tuesday.

"It should not be felt that the brazen denial and the lack of a proper response from the government of Pakistan to our repeated demarches on this incident will be ignored and that bilateral relations could be unaffected or that there will be business as usual," Khurshid said.

Calling the Pakistani army's purported actions "in contravention of all norms of international conduct," and a "grave provocation," Khurshid said they shed doubts on Pakistan's seriousness about normalizing relations.

The chief of the Indian army has warned that India may strike back. "If provoked, we will retaliate," Gen. Bikram Singh told reporters in New Delhi. "We reserve the right to retaliate at a time of our choosing."

Serious military action between the two nations, which have nuclear weapons, seems unlikely, analysts in India said in recent days. Still, civilians may be already be feeling an effect. On Tuesday, India was supposed to start a "visa on arrival" program for senior citizens from Pakistan. Instead, that program was put on hold, the Press Trust of India reported.