EU leaders are to hold emergency talks to discuss the political crisis in Belarus, after 10 days of protests that have shaken Alexander Lukashenko’s 26-year grip on power.

In the run-up to the meeting on Wednesday, the Belarusian opposition leader, Svetlana Tikhanovskaya, urged the EU not to recognise Lukashenko as president.

“I call on you not to recognise these fraudulent elections,” she said. “Mr Lukashenko has lost all the legitimacy in the eyes of our nation and the world.”

The bloc’s 27 heads of state will meet via video link from noon CET, where they are expected to issue a declaration of solidarity with the protest movement. They will also endorse a plan to sanction Belarusian officials who ran the disputed elections that resulted in an improbable landslide for Lukashenko, as well as those responsible for the violent political crackdown.

Lukashenko claimed victory in presidential elections 11 days ago after official results gave him 80% of the vote, with 10% to Tikhanovskaya. The EU said the contest was neither free nor fair.

“The people of Belarus have the right to determine their own future,” wrote the European council president, Charles Michel, in his summit invitation letter to leaders. “To allow for this, violence has to stop and a peaceful and inclusive dialogue has to be launched. The leadership of Belarus must reflect the will of the people. There should be no outside interference.”

EU leaders have been urged to deliver a warning against meddling by Russia, after Lukashenko called Vladimir Putin for help at the weekend.

On Tuesday, the leaders of Germany and France, Angela Merkel and Emmanuel Macron, spoke to the Russian president in separate phone calls. They set out their expectations that Lukashenko would refrain from violence, release political prisoners and open dialogue with the opposition. In both calls Putin spoke against “outside interference” in Belarus, according to Kremlin readouts.

Michel also spoke to the Russian leader. An EU official said they “discussed the best ways to encourage/assist intra-Belarusian dialogue for a peaceful end to the crisis”, adding that one option was dialogue through the Organization for Security and Cooperation in Europe.

The OSCE counts EU member states as well as Belarus and Russia among its members, but was denied access to monitor last week’s presidential elections.

So far Lukashenko has refused all offers to talk with the opposition. “He is desperately looking for the way out, not for the country but for himself,” said Lithuania’s foreign minister, Linas Linkevičius, who added that Lukashenko needed to be involved in any talks.

“We have to talk to everyone who is in possession of some leverage [including] those who are de-facto controlling power structures,” he told the Guardian this week.