- 1994: Post-Soviet peace pact -

After gaining independence from the Soviet Union in 1991, Ukraine on February 8, 1994 becomes one of the first former Soviet states to join NATO's "Partnership for Peace".

The programme provides for military cooperation with former communist countries.

Later that year, Ukraine agrees to give up the nuclear weapons it inherited from the Soviet Union in return for security guarantees from the United States, the United Kingdom and Russia.

- 2002: Seeking NATO membership -

On May 23, 2002, Ukrainian President Leonid Kuchma declares his country's NATO membership ambitions.

Three former Soviet satellites - Poland, Hungary and the Czech Republic -- have already joined.

NATO tells Kyiv to bide its time and continue implementing reforms.

Russian President Vladimir Putin says Ukraine is entitled to decide its own future but remains generally opposed to NATO's eastward expansion.

In 2004, seven other ex-communist states sign up: Bulgaria, Estonia, Latvia, Lithuania, Romania, Slovakia and Slovenia.

- 2008: German, French resistance -

At a summit in Bucharest in April 2008, NATO leaders defer putting Ukraine and fellow EU- and NATO hopeful Georgia on a formal path to membership but agree that the two former Soviet republics "will become members" at some point.

The United States had pushed hard on behalf of Georgia and Ukraine but Germany and France argued they were not ready for NATO membership.

- 2014: NATO slams Crimea grab -

On March 18, 2014, NATO secretary-general Anders Fogh Rasmussen condemns Russia's "illegal and illegitimate" annexation of Ukraine's Crimea peninsula, saying NATO will not recognise it.

NATO steps up its cooperation with the pro-European government that came to power in Ukraine's Maidan uprising.

- 2022: Russian invasion -

On September 30, 2022, Ukraine applies for expedited NATO membership, seven months after Russia launched a full-scale invasion of the country.

Finland has just become NATO's 31st member and Sweden's application is also being fast-tracked but Kyiv receives only a non-committal response.

In May 2023, Zelensky admits that it is not "realistic" to join while Ukraine is still fighting Russia, but that it wants "a very clear message that we will be in NATO after the war".

The White House says membership will come in the "not too distant future", but not at this week's NATO summit in Lithuania.