YEREVAN -- Armenian protest leader Nikol Pashinian has been detained in Yerevan during an opposition demonstration.
Pashinian was detained shortly after failed talks between him and Prime Minister Serzh Sarkisian. His current whereabouts is unclear.
Pashinian was confronted by masked police officers and other security personnel as he led a crowd of several hundred supporters marching to the city's southern Erebuni district. The police fired stun grenades to stop the march.
"People must liberate Nikol [Pashinian]," opposition lawmaker Sasun Mikaelyan told journalists before being detained himself by riot police, following 10 days of mass protests against an alleged power grab by Sarkisian.
Police also detained 49 protesters in the capital, official sources said.
The Armenian police later dismissed reports of Pashnian's detention and said in a statement that the opposition leader was "forcibly taken" from a protest rally in the capital.
"Despite repeated calls to stop illegal rallies, Pashinian continued leading a demonstration" in Yerevan, police said in a statement, adding that Pashinian and two other opposition lawmakers -- Mikaelyan and Ararat Mirzoyan -- "were forcibly taken from the site" as riot police dispersed the rally.
Earlier, Sarkisian walked out a meeting with Pashinian after accusing the opposition of "blackmail."
"I came here to discuss your resignation," Pashinian told the prime minister as the meeting began in Yerevan's Marriott Hotel.
"This is not a dialogue, this is blackmail," Sarkisian said before walking out of the meeting room where members of the media were present.
Before walking out, Sarkisian called on Pashinian, whose political alliance, he said, had "only six or seven percent of the vote" in parliamentary elections, not to speak on behalf of the people and not to issue ultimatums to the government.
Pashinian claimed Sarkisian had lost touch with reality and urged his supporters to turn out in larger numbers for peaceful civil-disobedience protests across the country.
He insisted that as long as the protests were peaceful the police should not break them up.
WATCH: LIVE broadcast of RFE/RL's Armenian Service from Yerevan
Sarkisian had said on April 21 that he sought a "political dialogue" with the protest leader.
"I will meet Serzh Sarkisian to discuss the conditions of his resignation and of [a] peaceful transfer of power," Pashinian said on April 21 on his Facebook page in a video message that came after nine days of mass demonstrations against Sarkisian's rule.
"I am deeply concerned about the inner-political developments. In order to avoid irreparable losses, I urge Nikol Pashinian to sit at the political dialogue and negotiations table. It should be done immediately," he said in a statement posted on his website.
Serzh Sarkisian was named prime minister after his 10-year stint as president ended two weeks ago.
Opponents says the shift effectively makes Serzh Sarkisian a leader for life. In a 2015 referendum, backed by Serzh Sarkisian, Armenia transitioned to a new system of government that reduces the presidency's power and bolsters the prime minister's role.
Pashinian met on April 21 with President Armen Sarkisian as protests mounted against Serzh Sarkisian's election as prime minister. The two Sarkisians are not related.
Flanked by bodyguards, Armen Sarkisian shook hands with the opposition lawmaker, and the two men spoke for around 10 minutes, before the president left the square.
Demonstrators in the Republic Square chanted "President, reject Serzh!" as Armen Sarkisian spoke with Pashinian.
Addressing the rally later in the evening, Pashinian said that during the brief conversation with the president he reiterated protesters' demand for the prime minister’s resignation.
Pashinian said he told the president that he would only negotiate with the government "the terms of Serzh Sarkisian’s resignation and a peaceful transition of power."
Hundreds have been detained in Yerevan in recent days as police seek to stop opposition supporters from blocking streets and paralyzing the capital.
Protesters also rallied in Armenia's second-largest city, Gyumri and in Vanadzor, the third-largest city in the country of about 3 million people. Several protesters were detained in Vanadzor on April 21.
In Artashat, a town about 30 kilometers south of Yerevan, Arus Hakobian, a correspondent for RFE/RL’s Armenian Service (Azatutyun.am), was assaulted while streaming live video for Azatutyun TV of an argument between government loyalists and opposition supporters.
Hakobian said that police officers present during the attack, which left the correspondent with a bloody mouth, did nothing to prevent the violence.
Armenian authorities have repeatedly warned journalists to stay "at a reasonable distance" from the sites where police are "carrying out their lawful actions."
The United States has urged both the authorities and protesters to exercise restraint and avoid violence, and Russia has said that laws should not be broken.
The OSCE's Office for Democratic Institutions and Human Rights (ODIHR) urged the Armenian authorities to protect and ensure the right to freedom of peaceful assembly in the country.
Serzh Sarkisian stepped down as president when Armen Sarkisian -- his handpicked successor -- was sworn in on April 9 after being elected by parliament. On April 17, parliament elected Serzh Sarkisian as prime minister -- a post that is more powerful than the presidency following the referendum.