Alexander Lukashenko under pressure as 2 rival protests planned in Belarus capital

Belarusian leader Alexander Lukashenko was under growing pressure on Sunday with rival protests due to converge on the capital a week after a contested presidential election that has thrown his country into turmoil.

Lukashenko, in power for 26 years, has faced down a week of street demonstrations and refused demands for a re-run of election protesters say was massively rigged to disguise the fact that he has lost public support.

He denies losing, citing official results that gave him just over 80 per cent of the vote.

Often emotional in-state TV appearances, the 65-year-old leader has alleged a foreign-backed plot to topple him. He has also cited promised military support from Russian President Vladimir Putin if necessary, something the Kremlin has not confirmed.

Russia, which has had a troubled relationship with Lukashenko, is watching closely as Belarus hosts pipelines that carry Russian energy exports to the West and is also viewed by Moscow as a buffer zone against NATO.

READ: Police, protesters clash in Belarus capital, Minsk, after vote

The EU is gearing up to impose new sanctions on Belarus in response to a violent crackdown in which at least two protesters have been killed and thousands detained.

Protesters show no signs of backing down.

Sviatlana Tsikhanouskaya, Lukashenko's opposition rival in the contested election, has called for a huge "March of Freedom" through the centre of Minsk, the Belarusian capital, starting at 11:00 GMT on Sunday.

Like previous protests, it is expected to culminate on Independence Square outside the main government building.

Just two hours before that, at 09:00 GMT, Lukashenko supporters are expected to hold a pro-government rally in central Minsk -- setting the stage for a potential confrontation between the two groups.

READ: Belarus President Lukashenko asks Vladimir Putin for help against riots

Metal fencing around Independence Square was being installed on Sunday morning with agricultural vehicles used to close off nearby roads.

Opposition media channels say Lukashenko, a one-time manager of a Soviet-era collective farm, plans to bus people in from other parts of the country and that they will be coerced into attending. Reuters could not independently confirm that.

Videos on social media showed long columns of buses with pro-Lukashenko supporters onboard driving towards Minsk from various regions.

'Wary Russia'

In an unusual move, Igor Leshchenya, the Belarusian ambassador to Slovakia, declared solidarity with protesters in an undated video posted by Nasha Niva media on Saturday. Other state employees, including police officers and state TV staff, have also come out in support of the protests.

Some of the country's biggest state-run industrial plants, the backbone of Lukashenko's Soviet-style economic model, have been hit by protests and walkouts in the past week.

Opposition presidential candidate Tsikhanouskaya, who fled to neighbouring Lithuania on Tuesday, has called for an election recount.

Her campaign has also announced she is starting to form a national council to facilitate a power transfer.

Lukashenko and Putin spoke by phone on Saturday.

READ: Belarus braces for weekend protests as pressure grows on President Lukashenko

Ties between the two traditional allies had been under strain before the election, as Russia scaled back subsidies that propped up Lukashenko's government.

The state news agency Belta on Saturday cited remarks by Lukashenko that "at the first request, Russia will provide comprehensive assistance to ensure the security of Belarus in the event of external military threats".

A Kremlin statement made no mention of such assistance but said both sides expressed confidence that all problems in Belarus would be resolved soon.

Statements by both sides contained a pointed reference to a "union state" between the two countries.

The neighbours signed an agreement in 1999 that was supposed to create a unified state. That project was never properly implemented, however, and more recently Lukashenko had rejected calls by Moscow for closer economic and political ties as an assault on his country's sovereignty.