Lawyers (L) for ousted Ukrainian leader Viktor Yanukovych stand as a panel of three-judges begin to deliver the verdict of high treason against the former pro-Moscow president

A Ukrainian court on Thursday found ex-president Viktor Yanukovych guilty of high treason and sentenced him in absentia to 13 years in prison for asking Russia's Vladimir Putin to send troops to Ukraine.

In 2014, Yanukovych was ousted as a result of a bloody uprising after his attempts to quell it failed.

He fled the country and asked Putin to send troops to Ukraine to help restore his control over the country.

"Yanukovych committed a crime against the foundation of Ukraine's national security," judge Vladyslav Devyatko said in Kiev's Obolon district court.

Yanukovych was also found guilty of "complicity in waging an aggressive war against Ukraine," Devyatko said, adding his prison term would begin "the moment he is detained."

The 68-year-old former Ukrainian president did not attend the trial and is believed to be living in Russia.

Earlier in the day authorities had beefed up security around the court as judges took turns reading out their ruling.

The court in Kiev has held hearings on the case since 2017.

Yanukovych faces a number of other criminal probes including over usurpation of power and using force against demonstrators.

In late 2013, the Moscow-backed president sparked massive protests when he refused at the last minute to sign an association accord forging closer ties between Ukraine and the European Union.

More than 100 people were killed in the violence when riot police cracked down on protesters in Kiev's iconic "Maidan" square in 2014.

After Yanukovych fled the country, Putin revealed a special operation organised by Moscow that exfiltrated the Ukrainian leader.

Moscow annexed Ukraine's Crimea peninsula in 2014 and supported Russian-speaking insurgents in the east of the ex-Soviet country.

The conflict in eastern Ukraine has claimed more than 10,000 lives despite repeated international efforts to forge a lasting ceasefire.

Russia views the chain of events that led to Yanukovych's ouster as a coup orchestrated by Washington.

Yanukovych has all but vanished from view since his violent suppression of street protests and little is known about how Ukraine's former strongman passes his day.

- From eastern Ukraine -

Yanukovych was born in the now conflict-torn Donetsk region of eastern Ukraine.

For two decades he served as a transport manager in Donetsk before moving into politics in the late 1990s.

He became the region's governor in 1997, with close ties to local oligarchs, and eventually prime minister under president Leonid Kuchma in 2002.

In 2004, he was initially proclaimed the winner of a presidential election amid allegations of vote-rigging and charges of interference from Moscow.

The election triggered the pro-democracy Orange Revolution and was eventually declared fraudulent.

Six years later Yanukovych returned to beat Orange Revolution co-leader Yulia Tymoshenko in a bitter presidential contest.

In the years that followed, he became deeply unpopular for his corrupt, lavish lifestyle.