The two sides have deployed vast numbers of troops on their borders

Indian embassy officials Pramod Kamar Saxena and Makhan Singh were accused of "activities incompatible with their official status," a foreign ministry spokesman said in a statement.

The statement, distributed by the state-run Associated Press of Pakistan, said the two were now "personae non grata".

The Indian High Commission had been informed that the pair must leave Pakistan by 26 March, the statement said.

Indian expelled two Pakistani embassy employees in Delhi earlier this month for allegedly receiving classified documents from Indian Muslims.

Tit-for-tat

Tensions between the two nuclear rivals have intensified since militants launched a suicide attack on India's parliament in December.

Delhi blamed Pakistani intelligence for masterminding the attack, a charge vigorously denied by Islamabad.

The two sides have since deployed hundreds of thousands of troops along their border in the biggest military build-up in the subcontinent in 30 years.

Shortly after the attack, India banned Pakistan's national airline from flying in Indian air space and reduced by half India's diplomatic staff in Islamabad and Pakistan's diplomats in Delhi.

Pakistan retaliated almost immediately, with similar restrictions.

The Indian sanctions were aimed at forcing Pakistan to take action against two Kashmir militant groups blamed for the suicide attack.

Delhi still wants Islamabad to extradite 20 suspects wanted for crimes in India, despite a pledge by Pakistani President Pervez Musharraf to crack down on Islamic extremism.

Pakistan has rejected the demand, saying that it will prosecute the suspects if Delhi provides credible evidence against them.

India and Pakistan have fought three wars since 1947.