A deadly attack on tourists in the disputed Kashmir last week has plunged relations between India and Pakistan to new lows, with both sides hinting at imminent military action.

Pakistan is bracing for Indian military action before Thursday night, officials warned, but cautioned that neither side would benefit from a return to war.

The US has urged India and Pakistan to work together to "de-escalate tensions" after a deadly militant attack in Indian-administered Kashmir last week killed 26 civilians. Secretary of State Marco Rubio held separate talks with India's foreign minister and Pakistan's prime minister on Wednesday and called on them to "maintain peace and security in South Asia".