India and Pakistan have agreed to set up a new telephone hotline to alert each to potential nuclear risks.
Neither side is currently able to recall a nuclear missile fired in error
The two sides, who held two days of talks in Delhi, said the aim was to prevent misunderstandings.
The nuclear neighbours, who came close to war two years ago, also agreed to continue a moratorium on nuclear weapons testing in place since 1998.
But tests could resume if either country believed "extraordinary events" threatened its interests.
The telephone hotline is to be set up between the most senior officials in the Indian and Pakistani foreign ministries, while an existing hotline between senior military commanders is to be "upgraded, dedicated and secured."
The BBC's Adam Mynott in Delhi says that while the countries talk regularly about nuclear issues, there has been real concern that should there be a nuclear accident the situation could escalate out of control.
Both countries have limited command and control structures, and neither has developed the technology to recall a nuclear-tipped missile fired in error.
India and Pakistan also reaffirmed each side would continue with a moratorium on nuclear tests, "unless in the exercise of national sovereignty, it decides that extraordinary events have jeopardised its supreme interests."
Further meetings are scheduled on a range of issues
The two countries have fought three wars since independence in 1947, and came close to conflict again two years ago.
But our correspondent says it is clear that the improvement in relations since then is continuing under the new Indian government.
The talks are part of a series of meetings over the next few weeks.
The agreement also paves the way for a planned first meeting between the two foreign ministers in China, where they are to discuss a range of issues on the sidelines of a regional conference.
India has said it would not be the first to use nuclear weapons, but Pakistan - which has far fewer conventional weapons - has not made such a commitment.
Three years ago, a preliminary agreement required both sides to give advanced notification of missile tests. But further talks were postponed after the December 2001 attack on the Indian parliament building, which Delhi blamed on Pakistani-backed militants.
Ties have thawed since last year's peace initiatives between Pakistani President Pervez Musharraf and former Indian Prime Minister Atal Behari Vajpayee.
A number of confidence-building measures have been introduced over the past year, including a resumption of rail, air and bus links and a strengthening of diplomatic ties.
The Indian cricket team also toured Pakistan earlier this year, despite security concerns.