ISLAMABAD - Pakistan and India announced on Thursday they would each expel one of the other’s diplomats amid growing tension between the nuclear-armed arch-foes over the disputed region of Kashmir.

Earlier in the day, New Delhi announced it was expelling a Pakistani visa official for suspected spying, with Islamabad responding by saying it would send back an Indian diplomat in an apparent tit-for-tat move.

Delhi police said the Pakistani official had been recruiting Indian nationals for two and a half years to spy for Pakistan in return for cash. “Delhi police crime branch has busted an espionage racket run by a kingpin working in the Pakistan high commission,” said Ravindra Yadav, joint commissioner of police on crime.

The official, named as Mehmood Akhtar, was detained on Wednesday with documents in his possession on Indian troop deployment along the border, Yadav told a press conference in Delhi.

“They used to meet once in a month at a pre-decided place to exchange documents and money,” he said. Akhtar was later released, he added.

Yadav said two Indian nationals from the northern state of Rajasthan were also arrested, and that Akhtar had planned to meet his Indian co-conspirators at the Delhi zoo to exchange the information and cash.

India’s foreign secretary Subrahmanyam Jaishankar summoned Pakistan’s high commissioner to inform him of the decision to expel the official within 48 hours.

“FS (foreign secretary) summons Pak High Commissioner to convey that Pak High Commission staffer has been declared persona non grata for espionage activities,” Indian foreign ministry spokesman Vikas Swarup said on Twitter.

Another Indian national was arrested late Thursday from the western Jodhpur city on charges of helping the Pakistan official, a senior police officer said.

Pakistan’s foreign secretary then summoned Indian High Commissioner Gautam Bambawale on Thursday night to say Islamabad would also be sending back a diplomat over alleged improper activities.

“The foreign secretary expressed deep concern over the activities of the Indian official that were in violation of the Vienna Convention and the established diplomatic norms,” an official statement said. It named the official as Surjeet Singh and added he and his family would also be required to leave within two days.

An aide to India’s prime minister in New Delhi said the government was looking into the matter. India’s external affairs ministry spokesman was not immediately available for comment on the expulsion by Pakistan.

The Foreign Office earlier issued a statement in Islamabad condemning the Indian action.

This was the third day running that a senior Indian diplomat was called to the Foreign Office. Earlier, Indian Deputy High Commissioner JP Singh was summoned for two consecutive days.

The Foreign Office rejected Indian allegations and deplored the Indian action, terming it a violation of the Vienna Convention as well as norms of diplomatic conduct, especially in an already vitiated atmosphere.

“We condemn the detention and manhandling of our diplomatic official,” the FO statement said.

The statement further said Pakistan High Commission had always been working within the parameters of international law and diplomatic norms. “This act clearly reflects Indian actions to shrink diplomatic space for the working of Pakistan High Commission,” added the statement.

A strong protest was registered by Pakistan High Commissioner Abdul Basit over the arrest of the staff member. Basit met the Indian foreign secretary after he was summoned at the foreign ministry. “Detention of the Pakistani diplomat is violation of the Vienna Convention,” Abdul Basit said.

“We reject the Indian allegations and deplore the Indian action which is indeed a violation of the Vienna Convention as well as the norms of diplomatic conduct especially in an already vitiated atmosphere,” the Pakistani High Commission said in a statement.

“Pakistan High Commission has always been working within the parameters of international law and diplomatic norms.”

Tensions were already high between the two neighbours, with deadly violence in Indian-held Kashmir over the death on July 8 of a popular militant leader.

Nearly 90 people, most of them young protesters, have been killed in clashes with security forces in Indian-occupied Kashmir.