India said on Tuesday it intended to expel half the staff in Pakistan's embassy in New Delhi over what it said was spying by officials there.
"They have been engaged in acts of espionage and maintained dealings with terrorist organizations," the Indian foreign ministry said in a statement.
India will cut staff in its own embassy in Islamabad by the same amount, the statement added.
A spokesman at Pakistan's embassy in New Delhi did not immediately respond to a request for comment.
India expelled two Pakistani diplomats on May 31 after they were held for alleged spying, claims Islamabad said were "baseless".
Relations between the nuclear-armed rivals are strained and tit-for-tat expulsions of diplomats, often on charges of espionage, are common.
Neither country has a permanent ambassador in place and in the last month, each has accused the other of the illegal detention and torture of diplomats.