Large numbers of police surrounded the crowds of demonstrators, some wrapped in Armenian flags.

Police said they detained 63 people for attempting to block roads. All were released soon afterwards.

At a previous demonstration on Monday, police briefly detained around 150 protesters.

The government has agreed to hand over to neighbouring Azerbaijan territory it has controlled since the 1990s.

Yerevan has started border delimitation efforts, in a bid to secure an elusive peace deal with Baku and avoid a fresh conflict between the two.

But the territorial concessions have sparked weeks of protests by demonstrators who have blocked major roads in an attempt to force Prime Minister Nikol Pashinyan to change course.

Two opposition lawmakers attended Tuesday's demonstration led by Archbishop Bagrat Galstanyan, who addressed protesters through a loudspeaker, dressed in black robes.

Galstanyan, a church leader from the Tavush region, where villages are set to be handed over to Azerbaijan, is seeking to launch an impeachment process against Pashinyan.

This initially requires protesters to present an alternative prime ministerial candidate and for 36 lawmakers to vote in favour of the impeachment process.

- Impeachment bid -

The opposition has not yet presented a candidate. Galstanyan, 52, is not eligible because he has joint Armenian and Canadian citizenship.

Parliamentary opposition factions have 35 lawmakers, meaning the protesters must also secure support from an independent MP or someone from Pashinyan's party.

Galstanyan has said an independent MP, Ishkhan Zakaryan, has agreed to vote in favour.

After these hurdles are overcome, an impeachment vote would need to be held within three days and would require 54 votes in favour to be successful.

Armenia and Azerbaijan, two former Soviet republics in the south Caucasus, have been locked in a stand-off over disputed territory, primarily Nagorno-Karabakh, since the break-up of the Soviet Union.

The two countries announced last month they had begun border demarcation work as part of efforts to normalise relations.

Pashinyan is currently in Denmark attending a democracy summit set up by former NATO secretary general Anders Fogh Rasmussen.

The former journalist became Armenia's prime minister in 2018 after leading peaceful street protests.

He cracked down on corruption and introduced popular judicial reforms but infuriated many Armenians by agreeing in 2020 to return parts of Nagorno-Karabakh to Baku.

Azerbaijan recaptured Nagorno-Karabakh in a lightning military offensive in September and talks over a broader border agreement have since intensified.