According to UK-based media reports, Pochettino allegedly had a long-lasting conflict with club chairman Daniel Levy.
"We were extremely reluctant to make this change and it is not a decision the Board has taken lightly, nor in haste [...] Regrettably domestic results at the end of last season and beginning of this season have been extremely disappointing", Levy said in the statement.
Club statement— Tottenham Hotspur (@SpursOfficial) 19 November 2019
According to The Telegraph, citing sources, Pochettino was devastated by the Champions League final defeat against Liverpool earlier this year and reportedly held a unique vision for the team's future roster, which contradicted Levy's stance.
The club also said in the statement that the Argentine, along with his coaching staff of Jesus Perez, Miguel D’Agostino and Antoni Jimenez, have been relieved of their duties.
Media have noted that Levy must pay a high compensation to part ways with Pochettino and his staff, all of whom had signed new five-year contracts in May 2018.
Pochettino was at the helm for 293 games and delivered four successive top-four Premier League finishes, challenging for the title in 2015/16 and 2016/17.