Yerevan: Armenia is facing a deepening political crisis, after talks between Prime Minister Serzh Sarkosian and protest leader Nikol Pashinyan failed and riot police clashed with demonstrators on Sunday.

Here are some key dates in the country’s recent history:

— Independence from USSR —

On September 23, 1991 Armenia declares independence from the crumbling Soviet Union after a landslide referendum.

Former dissident Levon Ter-Petrosyan goes on to win the country’s first presidential election.

Two months later, Armenia becomes a member of the Commonwealth of Independent States (CIS) before being admitted into the United Nations in 1992.

In the early days of its independence a revolt breaks out involving the ethnic Armenian population of Nagorny Karabakh, an enclave in neighbouring Azerbaijan.

The resulting war claims more than 30,000 lives before ending with a ceasefire in 1994 but the region’s status remains unsettled, despite years of diplomatic talks.

Isolated in his attempts at finding a resolution to the conflict, Ter-Petrosyan resigns in 1998 and is replaced by Robert Kocharian.

— Contested elections —

In 1999 gunmen storm the parliament building and kill nationalist prime minister Vazgen Sarkisian and six other politicians.

The killings are criticised by the authorities as an attempted coup and generate several months of political crisis.

Kocharian is re-elected in 2003 for a second five-year term in a vote marred by irregularities, according to the Organisation for Security and Cooperation in Europe.

In 2008 the pro-Russian and former army officer Serzh Sarkisian wins the presidential election in the first round, which the opposition denounces as fraudulent.

Bloody clashes between police and supporters of defeated opposition candidate Ter-Petrosyan break out at the start of March the same year, leaving 10 dead and hundreds injured.

— Turkey stalemate —

In 2009 Armenia and Turkey sign an agreement to normalise relations.

The so-called Zurich protocols would lead to the opening up of the border between the two neighbours, still haunted by the massacre of Armenians during the First World War.

The massacre of some 1.5 million Armenians by Ottoman forces between 1915-1917 is formally recognised as genocide by some two dozen countries including France and Russia. Turkey rejects the description.

The Zurich protocols are never ratified and in 2018 the government issues a decree to ditch the process.

— Controversial reform —

In 2013 Sarkisian is re-elected, after a crushing victory by his party in legislative elections a year earlier.

Two years later daily protests paralyse the capital Yerevan for two months after the government’s controversial move to hike electricity prices.

In December 2015 a constitutional referendum transforms the country into a parliamentary republic, a reform disputed by the opposition, calling it a move by Sarkisian to remain in power after the end of his term in 2018.

The constitutional amendments transfer governing powers from the presidency to the prime minister.

— Protests against new PM —

In July 2016 pro-opposition gunmen seize a police station in Yerevan, taking police officers and medical personnel hostage, which leaves two officers dead and triggers mass anti-government protests.

The following year Sarkisian’s republican party overwhelmingly wins legislative elections in a disputed vote.

In March 2018 lawmakers elect Armen Sarkisian, no relation to the outgoing Serzh Sarkisian, as the new president, a now largely ceremonial role under the new system.

On April 17, 2018, despite days of protests gripping Yerevan, the parliament elects the former president Serzh Sarkisian to become prime minister.