Pakistan's military vowed a strong response to any international attempt to seize its atomic arsenal as the army successfully test-fired a nuclear-capable cruise missile on Tuesday.
The security of Pakistan's estimated 50 nuclear warheads has been under global scrutiny since President Pervez Musharraf imposed a state of emergency on November 3 citing Islamist violence and political turmoil.
But the chairman of Pakistan's joint chiefs of staff, General Tariq Majid, blasted reports by "vested and hostile elements in the international media" about the security of its nuclear weapons, an army statement said.
"Suggestions have been made that our assets could either be neutralised or taken away towards safer place to prevent them from falling into wrong hands," the statement quoted Majid as saying after witnessing the launch of the locally developed Babur (Hatf 7) cruise missile.
"We remain alert to such threats and are fully capable of handling these."
The statement added: "Though no responsible state in the world can contemplate such an impossible operation, yet if someone did create such a scenario he was confident that Pakistan would meet the challenge strongly.
"Pakistan's nuclear assets are very safe and secure, and the nation need not to worry on that account. There is a very strong security system in place, which can ward off all threats, internal as well as external."
Musharraf and caretaker Prime Minister Mohammedmian Soomro congratulated scientists and engineers involved in Tuesday's test launch "on this very important success", the statement said.
The statement said that the test of the 700-kilometre (440-mile) range Babur missile would "consolidate Pakistan's strategic capability and strengthen national security".
"The Babur, which has near stealth capabilities, is a low-flying, terrain-hugging missile with high manoeuvrability, pinpoint accuracy and radar-avoidance features," it said.
"The missile test is part of a continuous process of validating the design parameters set for this weapon system."
Pakistan previously tested the missile in March and again in July. It was first fired in 2005, when its range was only 500 kilometres.
Pakistan confirmed last month that the United States was helping it ensure the security of its atomic weapons and shrugged off reports of a secret programme with Washington as nothing new.
The foreign ministry said the strategic arms were safe and secure under a tight command-and-control structure run entirely by Pakistan, and angrily dismissed fears that they could fall into the wrong hands.
A New York Times report had earlier said Washington was helping ensure their security in a top-secret programme that has cost the United States almost 100 million dollars since 2001, even though Islamabad refuses to allow US inspectors into its nuclear sites.
Advances by Taliban militants in the country's northwestern regions bordering Afghanistan have fuelled fears abroad that hardliners could either threaten Pakistan's nuclear weapons or even stage a takeover.