India will help train Afghan security forces under a deal signed by Indian Prime Minister Manmohan Singh and Afghan President Hamid Karzai, according to a copy of the agreement released by India.
The two nations agreed on a wide range of political, trade and person-to-person links under the strategic partnership deal signed Tuesday.
The agreement comes at a time of increasing tension between Afghanistan and Pakistan, India's fiercest regional rival.
Pakistani Prime Minister Yusuf Raza Gilani on Wednesday downplayed the significance of the agreement.
"It does not make a difference to Pakistan, nor does it cause Pakistan any harm," he said on GEO TV.
But Kanwal Sibal, a former Indian foreign secretary, laid out the regional tensions to CNN on Wednesday.
"Pakistan continues to press the international community to reduce India's role in Afghanistan, but that position has been effectively rejected by the United States," he said at a conference on the region in London.
"Pakistan cannot have a veto over the right of a sovereign, independent Afghan government to have a relationship with India," he said.
But, he added: "We have no interest in getting involved in the military situation in Afghanistan, so Pakistan has no reason to worry."
One expert on the region refused to predict what effect the deal would have.
"South Asia is a paradox. There are no consistencies in relationships between countries," said Sajjan Gohel, director for international security at the Asia-Pacific Foundation. "What may be the current understanding could well be very different in six months' time."
Relations between Afghanistan and Pakistan are particularly poor at the moment.
Afghanistan said this week that Pakistan's intelligence agency played a role in the assassination of a former Afghan president turned key peace negotiator.
Burhanuddin Rabbani, who was spearheading the reconciliation process with the Taliban in Afghanistan, was killed in a September 20 suicide bombing at his home.
"There are no doubts that ISI had its involvement in the plot," Interior Minister Bismillah Mohammadi told Afghan lawmakers, referring to Pakistan's Inter-Services Intelligence agency. "We have handed over the documents and proof to the Pakistani government."
Pakistan's Foreign Ministry denied the claims, calling them "baseless allegations."
Pakistan did not comment on the India-Afghanistan agreement and did not respond to questions from CNN about it Wednesday.
The deal notes that it is "not directed against any other state or group of states."
It also includes a promise of Afghan support for India's quest to get a permanent seat on the United Nations Security Council.