Police have ended their two-day stakeout of an apartment block in which Cameroon's main opposition leader Maurice Kamto had been staying after he returned from France, where he had held a political rally that inflamed the ruling CPDM party.

On Sunday law enforcement officers blocked the 71-year-old from leaving the building in the main city of Douala for a meeting with members of his Cameroon Renaissance Movement (CRM) party.

He later called off plans to hold the meeting on Monday, and left for the capital, Yaoundé.

Kamto plans to contest the presidential election later this year, hoping to end 92-year-old Paul Biya's four-decade grip on power.

Biya has not yet declared whether he will stand for re-election.

Kamto spent nine months in detention after contesting the 2018 poll, when the authorities accused the former law professor of insurrection following protests by his supporters who claimed that the poll had been rigged in favour of Biya. The government denied the allegation.

While in Paris last month, Kamto promised he would protect Biya and his family if he wins October's election.

"When you do me the great of honour of entrusting me with the reins, you can be sure that nothing will happen to Mr Biya and his family. Nothing. I guarantee it, I have no time for hatred. I [only] have time to build Cameroon with you," he told thousands of Cameroonians living in the diaspora who had turned up to his rally on 31 May.

This did not go down well with ruling party officials, with one calling his comments "pathetic".

"What protection do they need? Which family are we talking about?," asked Labour Minister Grégoire Owona in a Facebook post, adding, "Cameroon is not in danger."

Following Kamto's return, security was tightened in parts of Douala.

Police officers on the ground told the BBC on Monday that they had been instructed to watch the neighbourhood where Kamto was staying, and the media was not allowed to film.

Footage filmed in the port city on Sunday evening showed Kamto telling supporters "as I speak, I'm still sequestered".

"Go home in calm and dignity," he told chanting supporters who had gathered at the scene.

Police and gendarme officers had also restricted access to the CRM party building in Douala that Kamto was trying to reach, saying the meeting was not authorised.

But Kamto denies this, saying local authorities and law enforcement officials were informed that he was coming to the city for a meeting.

As the election approaches, rights groups have condemned the government's crackdown on dissent in the Central African nation.

Parliamentary elections that were also supposed to take place earlier this year have been delayed until 2026.

Biya has been in power for 42 years and is one of the world's oldest heads of state.

Last year the country banned reports on the president's health, following rumours that he had died.

Kamto's eligibility to run for the presidency is in question, because Cameroonian law demands that any political party must already have elected representatives in place if its leader wishes to run for president.

At the last presidential election Kamto's CRM party had one senator, but going into this election it has no elected officials.

Alternatively Kamto could run as an independent candidate, for which he would need 300 signatures from designated personalities from across the country.

Yet Kamto insists there is "no legal obstacle" stopping his bid for the presidency, and CRM representative Guy Tassé told the AFP news agency that there was "a political manoeuvre by the regime to try to block the candidate they fear because he embodies real change".

The country is also in the throes of a separatist insurgency – with rebels demanding independence for Cameroon's two English-speaking provinces, which are home to 20% of the population.

In the near-decade since the conflict began, at least 6,000 people have been killed and hundreds of thousands forced from their homes.

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