"The deterioration in Celso's relations with the fans was one of the factors that motivated our decision," Inter vice-president Roberto Siegmann told a news conference at the Beira-Rio stadium in the southern city of Porto Alegre.
Inter, who won the Libertadores Cup for the second time last year, have struggled to defend their title this season, steering perilously close to elimination at the group stage.
Roth took over from Uruguayan Jorge Fossati ahead of the semi-finals of last season's competition and won the trophy but failed in December to steer Inter into the final of the Club World Cup, a competition they won in 2006.
The 53-year-old Roth's dismissal comes two days after Inter lost 1-0 away to Chiapas of Mexico playing poorly and putting their qualification in Group Six of the Libertadores Cup in jeopardy.
A draw would have been enough to secure Inter's place in the last 16. Instead they face a tough home decider against Emelec of Ecuador in Porto Alegre on April 19. Inter lead the group with 10 points, one more than Chiapas and two ahead of Emelec.
Roth had been living on borrowed time since December when Inter became the first team from the two big soccer continents, South America and Europe, to fail to reach the final of the Club World Cup and its predecessor, the Intercontinental Cup.
MID-EAST DISAPPOINTMENT
More than 10,000 Inter fans made the long trip to the Middle East, where Roth had once worked, expecting to watch their team contest the final against European champions Inter Milan only to see them upset 2-0 by Congolese African champions TP Mazembe in their semi-final.
Inter have since been inconsistent in the Libertadores Cup and the Gaucho (Rio Grande do Sul) state championship which precedes their participation in the Brazilian championship starting in May.
Media reports said former Inter, AS Roma and Brazil midfielder Paulo Roberto Falcao, who is working at a TV pundit, was favourite to succeed Roth.
Siegmann, Inter's vice-president for football, however, told the club's official website a decision had not been made on a replacement.
"It's still not decided. The names being mentioned are mere speculation," he said.
"We've already had contact with some professionals. In any case, I'm working to get the situation resolved as quickly as possible."
