Pakistan says it has fired its first cruise missile, describing the launch as a "milestone" in its history.
Cruise missiles can be targeted with pinpoint accuracy
The Babur missile is capable of carrying nuclear and conventional warheads and has a range of 500km (310 miles), a military spokesman said.
Information Minister Sheikh Rashid Ahmed said the launch was a birthday gift to President Pervez Musharraf.
Analysts say the launch is likely to cause concern in the region. Nuclear rival India had no comment.
The launch comes days after Pakistan and India agreed to give each other advance notice of future nuclear ballistic missile tests.
India was not informed about Thursday's test because the agreement did not cover guided missiles, a Pakistan military spokesman said.
Mr Ahmed said the "milestone" launch had been a success, adding: "The nation is proud of its team of scientists who have raised the country's prestige in the comity of nations."
He said it was a gift from scientists to Gen Musharraf, 62 on Thursday.
Cruise missiles are usually low-flying guided missiles.
"The technology enables the missile to avoid radar detection and penetrate undetected through any hostile defensive system," the Pakistan military said in a statement.
Pakistan has its own range of intermediate and short-range ballistic missiles which are test-fired quite regularly.
Army spokesman Maj Gen Shaukat Sultan said Pakistan had now joined the few countries "that can design and make cruise missiles".
Separately, the UK has said it will ease curbs on the export of nuclear technology to India.
Foreign Secretary Jack Straw cited Delhi's improved relations with Islamabad, its commitment to nuclear non-proliferation standards and to tackling climate change as reasons for the decision.
Last month, US President George W Bush said he would seek congressional approval for a plan to help develop India's civilian nuclear programme, reversing existing US policy.
The UK Foreign Office said it was also discussing co-operation on nuclear issues with Pakistan.
The BBC's Zaffar Abbas in Islamabad says Pakistan's cruise missile test is likely to ring alarm bells in many countries.
Pakistan already has intermediate-range nuclear missiles
Pakistan has been under close scrutiny by the international community since its leading nuclear expert, AQ Khan, was found to have leaked nuclear secrets two years ago.
India and Pakistan routinely test-fire their missiles.
In March, Pakistan successfully tested a long-range nuclear-capable missile - the Shaheen II, with a range of 2,000km (1,250 miles).
The two countries have twice veered close to war since their nuclear tests in 1998 - over Kashmir in 1999 and again in 2002.
Both countries have limited command-and-control structures, and neither has developed the technology to recall a nuclear-tipped missile fired in error.