The cosmonaut celebrated the achievement on board the International Space Station.
Russian cosmonaut Oleg Kononenko set a world record on Sunday for the most time spent in space. He spent over 878 days and 12 hours outside the Earth's atmosphere, totalling nearly two and a half years, as per a report in Sky News.
The 59-year-old surpassed the milestone of his compatriot Gennady Padalka, who was in space for a total of 878 days, 11 hours, 29 minutes and 48 seconds across five space journeys before retiring in 2017.
The cosmonaut celebrated the achievement on board the International Space Station. "I fly into space to do what I love, not to set records. I've dreamt of and aspired to become a cosmonaut since I was a child. That interest - the opportunity to fly into space, to live and work in orbit - motivates me to continue flying," he told Russian news agency TASS.
Mr Kononenko added: "I am proud of all my achievements, but I am more proud that the record for the total duration of human stay in space is still held by a Russian cosmonaut."
Mr Kononenko, who is the commander of the Russian space agency Roscosmos cosmonaut corps, is on his fifth space mission. Alongside fellow Russian Nikolai Chub and NASA astronaut Loral O'Hara, he began his current mission to the International Space Station on September 15, 2023.
He will complete 1000 days in space on June 5, this year, making him the first person to achieve this feat. Further, he will have spent 1,110 days in space when his current expedition trip, which is planned to end on September 23, is completed.
The 59-year-old said that he did not feel "deprived or isolated" since he could video call his relatives and do regular exercises. However, he said that not seeing his children in front of his eyes is difficult. "It is only upon returning home that the realisation comes that for hundreds of days in my absence the children have been growing up without a papa. No one will return this time to me."
Meanwhile, the ISS is one of the few international projects on which the United States and Russia still cooperate closely. In December, Roscosmos said that a cross-flight programme with NASA to the ISS had been extended until 2025. Relations in other areas between the two countries have broken down since Russia's invasion of Ukraine nearly two years ago, to which Washington responded by sending arms to Kyiv and imposing successive rounds of sanctions on Moscow.