Pakistan said yesterday it reserved the right to take "all appropriate" steps for its security following India's nuclear tests.
A statement from the Foreign Minister, Mr Gohar Ayub Khan, said: "The responsibility for dealing a death blow to the global efforts at nuclear non-proliferation rests squarely with India."
Mr Khan told the upper house of parliament, almost five hours after India carried out the tests in the Rajasthan western desert, that the news of the resumption of nuclear testing by India "has not come as a surprise to us".
"For the past 24 years Pakistan has consistently drawn the attention of the international community to India's nuclear aspirations.
"We had also pointed out the duplicity surrounding India's political pronouncements and its clandestine nuclear weapons programme."
Mr Khan said the Pakistani Prime Minister, Mr Nawaz Sharif, had recently drawn the attention of the permanent members of the UN Security Council regarding an "Indian plan to induct nuclear weapons". Pakistan's repeated reminders to the international community "unfortunately did not receive the attention that they merited", he added.
"The international community has, in fact, by adopting a dismissive approach, encouraged India to achieve its nuclear aspirations."
Mr Khan said Pakistan, another nuclear threshold power, "reserves the right to take all appropriate measures for its security" and "such threats will be met by the determination of the Pakistani nation".
Mr Khan told reporters that the defence committee of prime minister's cabinet could decide whether Pakistan should also carry out a nuclear test in response to yesterday's Indian explosions near Pakistan's border. Asked if Pakistan would respond to the Indian tests in the same manner, Mr Khan said: "It's not for me to say. It is for the defence committee of the cabinet to decide."
"They should be condemned very, very strongly and India has forced the subcontinent into an arms race, to a nuclear weaponry race and missile race," he told Reuters Television earlier.
He said Mr Sharif, who was due to return home late at night after attending a summit in Kazakhstan, had assured Pakistanis that the country's "defence would be made impregnable against any Indian threat, be it nuclear or conventional".
Australia said it would lodge a strong diplomatic protest with India over its nuclear tests and recall its top diplomat in New Delhi.
The Foreign Minister, Mr Alexander Downer, said the Indian tests would fuel regional tensions and had outraged a world fighting to move on from the nuclear weapons age.
Japan, the only nation to suffer atomic bombing, strongly denounced India's nuclear tests and called on other nations in the region to show "self-restraint" in their reaction to the testing.
New Zealand lodged an official protest with the Indian government over its nuclear tests yesterday. The Foreign Minister, Mr Don McKinnon, said "this is a real gross insult to the whole world - pull back before it is too late".