Models of a North Korean Scud-B missile and South Korean missiles are displayed at the Korean War Memorial Museum in Seoul
Models of a North Korean Scud-B missile, right, and South Korean missiles are displayed at the Korean War Memorial Museum in Seoul. While the North has already conducted two successful nuclear tests, experts do not believe the country has mastered the technology necessary to build a nuclear warhead and mount it on a missile. REUTERS/Lee Jae-Won

North Korea has invited United Nations nuclear inspectors into the country for the first time in three years, in a bid to kick-start aid talks with the United States.

The invitation by the North's chief nuclear negotiator, Ri Yong-ho, follows an agreement in February to suspend the testing of nuclear and long-range ballistic missiles while also allowing international inspections in exchange for humanitarian shipments of food to the isolated country.

Last week, however, North Korea announced plans to launch a rocket-mounted satellite, which would violate -- perhaps scuttle -- the recent agreement.

The Vienna-based International Atomic Energy Agency, the U.N. nuclear agency, said it received the invitation on Friday.

We will discuss with the DPRK and other parties concerned for the details of the visit, IAEA spokeswoman Gill Tudor said in an emailed statement. Details will be discussed. Nothing has been decided yet.

DPRK, or Democratic People's Republic of Korea, is the country's formal name.

The U.S. State Department welcomed news of the invitation, saying that in principle it supported all efforts by the IAEA to monitor North Korea's nuclear program.

But the announced missile launch -- set to mark the centenary of North Korea founder Kim Il-sung's birthday in April -- had undercut the deal, a State Department spokeswoman cautioned.

Obviously there's benefit for any access that the IAEA can get, Victoria Nuland said Monday. But it doesn't change the fact that we would consider a satellite launch a violation not only of their U.N. obligations but of the commitments they made to us.

In February, the United States agreed to supply food aid in return for the North's suspension of missile launches, nuclear testing and uranium enrichment.