India called on Thursday for isolation of countries deemed to be supporting terrorism, while Pakistan decried "brutal force" against civilians resisting occupation as the neighbours' rivalry spilled over into a regional conference.
Traditionally tense relations between Pakistan and India have been strained further in recent weeks by a flare-up in protests against Indian rule in its part of the border region of Kashmir, in which about 50 people have been killed.
Indian Interior Minister Rajnath Singh arrived in Islamabad on Wednesday for a meeting with counterparts from the South Asian Association for Regional Cooperation (SAARC).
Singh had already ruled out bilateral talks with Pakistan on the sidelines, and in his speech to the forum castigated any support for militants.
"One country's terrorist cannot be a martyr or freedom fighter for anyone," he said. "Those who provide support, encouragement, sanctuary, safe haven or any assistance to terrorism or terrorists must be isolated."
Singh did not mention Pakistan by name but India accuses its neighbour of sheltering militants fighting against Indian rule in its part of divided Kashmir.
Pakistan denies supporting militants but say it offers political support to the "freedom struggle" of the people of the Muslim-majority region.
Pakistani Interior Minister Nisar Ali Khan, in his remarks, "drew the attention of SAARC member states to the use of brutal force ...against unarmed civilians engaged in a struggle against foreign occupation", a barely-veiled reference to Kashmir.
Khan said he hoped the SAARC meeting could be a forum for "a lot of soul-searching on all sides".
"Maybe that will provide us with the opportunity for ... our leadership to sit together informally and work out solutions to the problem that have been afflicting this region ...Discussions which might not be possible in the glare of media publicity, heart-to-heart discussions," Khan told the opening session.
While Pakistan says Kashmir is at their heart of their decades of rivalry, India says its main issue is the militancy that it accuses Pakistan of sponsoring.
Efforts to get talks going have stuttered for decades, at times derailed by militants attack in India that it has blamed on Pakistan.
Their rivalry has hampered efforts to transform the eight-member SAARC into a useful forum for cooperation in South Asia, which accounts for a fifth of the world's population but less than a tenth of its economic output.