North Korea has agreed to suspend uranium enrichment, as well as nuclear and long-range missile tests, US and North Korean officials say.
The US State Department said the North had also agreed to allow UN inspectors to monitor its reactor in Yongbyon to verify compliance with the measures.
In return, Washington is set to provide Pyongyang with some 240,000 tonnes of food aid.
The move follows talks between US and North Korea in Beijing last week.
'First step'Correspondents say the move could pave the way for the resumption of six-party disarmament negotiations with Pyongyang, which last broke down in 2009.
"The United States still has profound concerns regarding North Korean behaviour across a wide range of areas, but today's announcement reflects important, if limited, progress in addressing some of these," State Department spokeswoman Victoria Nuland said.
US Secretary of State Hillary Clinton described the move as a "modest first step in the right direction".
She said the US would however be watching Pyongyang closely, and would be "judging North Korea's new leaders by their actions".
North Korea confirmed the move in a statement released simultaneously in Pyongyang.
The foreign ministry statement, carried by the KCNA news agency, said the measures were "aimed at building confidence for the improvement of relations" between the two countries, and said talks would continue.
Earlier, a senior US military official said the issue of food aid for North Korea was now linked to political progress - contradicting earlier policy.
The North has suffered persistent food shortages since a famine in the 1990s, and relies on foreign aid to feed its people.
The talks in Beijing were the first since Kim Jong-un succeeded his father, Kim Jong-il, as the head of the communist state in December, 2011.