Two officials at the Pakistan High Commission in New Delhi were being expelled for "indulging in espionage activities," India's foreign ministry said late Sunday, with tensions already heightened between the nuclear-armed rivals.

The South Asian neighbors have a long-running dispute over Kashmir, which was split between them in 1947 when they gained independence from Britain.

"The government has declared both these officials persona non grata for indulging in activities incompatible with their status as members of a diplomatic mission," the ministry said in a statement.

The pair had to leave the country "within 24 hours" and Pakistan's Charge de Affaires was issued with a "strong protest" over the alleged activities of the pair, the ministry said.

In Pakistan's capital, Islamabad, the foreign ministry condemned India’s decision about the expulsion of two of its embassy officials. In a statement, it said the two staff members of the Pakistani High Commission in New Delhi were lifted by Indian authorities Sunday on false and unsubstantiated charges.

"They were, however, released on intervention by the High Commission. We condemn the detention and torture as well as threatening and pressuring of diplomatic officials to accept false charges," it said.

Pakistan also summoned an Indian diplomat to lodge a strong protest over the move.

The expulsions came weeks after an Indian national was set to stand trial in Germany, accused of spying on Sikh and Kashmiri communities for New Delhi's secret service.

India and Pakistan routinely expel each other’s diplomats on spying charges and Pakistan is also expected to respond by expelling Indian High Commission officials in Islamabad in a tit-for-tat action.

India and Pakistan have fought three wars against each other since independence, including two over Kashmir.

Kashmir has become a bigger source of tension in the relations between the regional powers after New Delhi last year scrapped the restive Muslim-majority Himalayan region's semi-autonomous status and imposed a curfew to quell unrest.

Rebel groups in Indian-administered Kashmir have battled for decades for the region's independence or its merger with Pakistan and enjoy broad popular support.

The fighting has left tens of thousands dead, mostly civilians, since 1989.

India has more than 500,000 troops stationed in Kashmir.