Serzh Sarkisian has been sworn in for a second term as Armenia's president in the capital, Yerevan, amid an opposition challenge to the credibility of his reelection.
In his inaugural speech, Sarkisian set "our state’s and nation’s economic development [as] the No. 1 priority."
"A whole array of problems that Armenia is facing is on this very plane," the president said. "Let me highlight three main ones: emigration, unemployment, and poverty. The solutions for these problems are to be found on the same field -- an efficient economy that is on the rise, this is the formula to our success."
Sarkisian also said "a peaceful settlement of the Nagorno-Karabakh conflict will remain a priority." Armenia and neighboring Azerbaijan have been in conflict over Azerbaijan's breakaway, Armenian-populated region for more than two decades.
Sarkisian also expressed his gratitude to those who supported him in the presidential election.
Meanwhile, Sarkisian's main challenger in the February vote, Raffi Hovannisian, held what he had called an "alternative inauguration."
Hovannisian continues to dispute the result, and he took a self-administered pledge in front of thousands of opposition supporters in Yerevan’s Liberty Square.
WATCH: RFE/RL's Armenian Service interviews Hovannisian
In his address to the crowd, he called Sarkisian's inauguration "illegitimate."
Thousands of Hovannisian's supporters tried to march to a memorial using an avenue where the presidential palace is also located. RFE/RL's Armenian Service reports that there were some light skirmishes between the protesters and riot police, but that altogether the protest remained peaceful.
The Russian news agency Interfax said police detained a number of opposition activists.
The police suggested they would detain Hovannisian if he seemed to be trying to assume power after declaring himself Armenia's president.
The dispute had elicited fears among some Armenians of a repeat of deadly violence that followed Sarkisian's declared victory in the 2008 presidential election and left 10 people dead.
Sarkisian’s inauguration took place at the city’s largest concert hall.
Sarkisian won his second five-year term in the February 18 election with more than 58 percent of the vote, versus 37 percent for Hovannisian.
PHOTO GALLERY: Dual Inaugurations, Scuffles With Police
Armenian President Serzh Sarkisian (center) during his inauguration ceremony in Yerevan
President Serzh Sarkisian during his inauguration ceremony
Catholicos of All Armenians Karekin II blesses President Serzh Sarkisian during his inauguration ceremony.
Raffi Hovannisian kisses an Armenian flag during the opposition rally.
Raffi Hovannisian addresses his supporters during the rally in Yerevan.
Riot police detain young opposition activists in Yerevan.
Riot police confront opposition leader Raffi Hovannisian in Yerevan.
One of the supporters of opposition leader Raffi Hovannisian shouts during the rally against President Serzh Sarkisian's victory.
Clashes and arrests after Raffi Hovannisian's rally.
Armen Martirosian of Armenia's Heritage party is detained by police while participating in the opposition rally.
Riot police confront opposition protesters in Yerevan.
Supporters of opposition leader Raffi Hovannisian rally against President Serzh Sarkisian's victory in elections in Yerevan.
But Hovannisian claims to have been the real winner of the February 18 presidential election, and his protest ceremony was to be followed by daylong opposition rallies.
Hovannisian claimed the election was rigged and sent 70 complaints to the electoral commission.
The commission rejected the allegations, saying the documents were based neither on fact nor legal evidence.
On March 29, Hovannisian announced he was ending a two-week-old hunger strike to make sure he had enough energy to keep up his political work.
International monitors described the poll as an improvement on previous ones but said it lacked real competition after some of Sarkisian's rivals decided not to run.
With additional reporting by Reuters and Interfax
WATCH: Rival "inaugurations" for Armenian president, challenger