TIMELINE: North Korea's nuclear talks and agreements

(Reuters) - Christopher Hill, the chief U.S. envoy to nuclear disarmament talks with North Korea, on Thursday became the most senior State Department official to visit the communist state since 2002.

Here is a chronology of previous milestones.

* October 21, 1994: President Bill Clinton's U.S. administration signs an Agreed Framework with North Korea to freeze its nuclear program in exchange for aid, including two relatively proliferation-resistant nuclear reactors.

* October 2002: U.S. State Department envoy James Kelly confronts Pyongyang with evidence Washington says points to a covert uranium enrichment program.

* December 2002: North Korea says it plans to restart Yongbyon reactor, disables the International Atomic Energy Agency's (IAEA) surveillance devices there and expels the agency's inspectors.

* January 2003: Pyongyang quits nuclear Non-Proliferation Treaty.

* August 2003: First round of six-party talks between North and South Korea, China, Japan, Russia and the United States held in Beijing. North Korea threatens to test nuclear bomb and test-fire new missile.

* February 2004: Father of Pakistani nuclear bomb, scientist Abdul Qadeer Khan, admits he passed uranium-linked technology to Libya, Iran and North Korea. Pyongyang calls confession a lie.

* February 2005: North Korea officially says for the first time it has nuclear weapons, adding it is quitting six-party talks.

* September 2005: Six parties issue joint statement after months of deadlock. North Korea promises to give up nuclear arms program in exchange for aid and better diplomatic standing.

* July 2006: North Korea test-fires seven missiles from its east coast, including the long-range Taepodong-2.

* October 9, 2006: North Korea explodes first nuclear device.

* February 13, 2007: North Korea agrees to start shutting its reactor and allow U.N. nuclear inspectors back into country in exchange for aid, the first step in a new disarmament deal.

* June 14, 2007: Transfer begins of North Korean funds frozen at a Macau bank that Pyongyang had demanded be returned before it starts shutting reactor.

* June 20, 2007: Chief U.S. nuclear envoy Christopher Hill flies to Pyongyang.

Source: Reuters