Factbox-What are the key issues in the Cyprus conflict 50 years since invasion

NICOSIA - There will be celebrations in the north, and mourning in the south of Cyprus on Saturday, the 50th anniversary of a Turkish invasion triggered by a brief Greek inspired coup.

Here are some key issues relating to the conflict:

WHAT TRIGGERED THE DISPUTE?

- A British colony until 1960, Cyprus's Greek and Turkish Cypriots participated in power sharing until 1963, when a tax disagreement spilled over into an all-out dispute over the functioning of the government. The dispute left Greek Cypriots running the internationally recognised Republic of Cyprus.

- Violence erupted in December 1963, prompting the dispatch of a U.N. peacekeeping force to the island six months later. Turkish Cypriots withdrew into enclaves, effectively partitioning the capital Nicosia.

- Turkey, Britain and Greece were named guarantors of Cyprus's sovereignty in 1960, with rights to intervene if there is a breakdown of constitutional order.

Citing those rights, Ankara invaded Cyprus in July 1974 after the junta then ruling Greece staged a brief coup five days earlier which toppled the legitimate Cyprus government. The Cyprus crisis caused the collapse of Greece's seven-year military dictatorship. Constitutional order was swiftly restored on Cyprus, but Turkey never withdrew. Britain holds on to 3 percent of Cypriot territory known as sovereign base areas, partly for military purposes.

WHAT FORCES ARE PUSHING FOR RESOLUTION?

- Cyprus has been a member of the EU since 2004, but it is effectively represented by Greek Cypriots who have veto powers over Turkey joining the bloc.

- With Cyprus in the EU and Turkey in NATO, defence relations between the two organisations can be problematic, and it is also a source of tension between Turkey and Greece.

- Although it has been years since there was any violence between the two sides, 30,000 Turkish troops remain in the north and both sides have security concerns.

WHAT ARE THE KEY STUMBLING BLOCKS?

- Sovereignty: disputes focus on whether a peace deal should be an evolution of the present Republic of Cyprus, as advocated by Greek Cypriots, or a merging of two equal states advocated by Turkish Cypriots who seek recognition of their breakaway state.

- Guarantor system: an emotional trigger for both sides. Greek Cypriots want the system scrapped. Turkish Cypriots say they need Turkish guarantees because of their past experience with Greek Cypriots.

- Governance: how much say will go to each community in the context of a federal system, and what deadlock-easing mechanisms can be adopted for the smooth functioning of the state.

- Settlement and Property Disputes: a legal quagmire where thousands of individuals have claims on property seized decades ago.

-(Reuters)