Bo's wife, Gu Kailai, and a family employee are detained on suspicion of murdering Briton Neil Heywood. Bo has been suspended from powerful party positions while he is investigated. Official media also hinted this weekend that he too could face criminal charges, referring to possible breaches of law.
In an article for Communist party journal Seeking Truth, Wen said regional governments that allowed "important cases" of corruption or failed to act quickly would be held responsible. He promised reforms in areas relating to accountability and said governments should immediately investigate problems reported by the people and the media.
The party has repeatedly pledged to step up the fight against corruption.
Analysts say Bo's case presents top leaders with a dilemma. If they reveal only limited evidence against him, it may look as if a popular figure has been removed for political reasons. If the accusations are too shocking, people will ask how he could have become so powerful – and what other senior leaders may have been doing.
A separate piece by Xinhua said the case was "nothing to do with political struggle".
It warned: "In some places, there are some practices in which power and personal favour are put above the law … In some places, there are top officials making decisions without seeking others' opinions and thus violating the principle of democratic centralism. The spouses and children of some cadres have taken advantage of their power to seek personal gains."
In other cases officials "choose the road of abusing power for personal gains" because they cannot resist the temptations of the market economy, it said, adding that the party never tolerated breaches of discipline or the law, whoever was responsible.
"I think this is a very serious legitimacy crisis for the party," said Patricia Thornton, lecturer in politics of China at the University of Oxford. "As more details of the case come out, I think it will be very, very difficult to sustain that."
The more thorough and far-reaching the investigation, the more it would expose the ties of the party elite to powerful commercial interests, she said.
Bo's case has been particularly damaging, not merely because of his position but because he had significant grassroots support and a reputation as someone concerned about inequality, corruption, and crime, she added.
The South China Morning Post reported on Sunday that five inspection teams from the Central Military Commission are investigating links between Bo and senior officers in the Chengdu military region. He is well known for his ties to the army.
The deputy police chief of Chongqing and head of the municipal criminal police team have also been detained for their roles in the alleged cover-up of the Heywood case, reports say.
