China has recalled 247 criminals who are serving sentences outside the jail back into prison, as they were found to have not met the requirement for out-of-prison serving any more.

Among them are 18 former officials at or above the level of a deputy department head, the Supreme People's Procuratorate (SPP) revealed on Sunday.

Some of these criminals were canceled the remission of serving terms out of prison for they had been found to have gained the serving mode by illegal means, such as offering bribery, according to the top procuratorate.

The SPP said that it uncovered 188 cases involving illegal grant of commutation, parole and serving sentence outside jail in a special inspection from March to the end of May. It is investigating 30 cases concerning duty-related crimes, involving 40 officials in the judical system.

During the inspection, the SPP found Shi(surname), a prison leader in east China's Jiangsu Province, taking bribes worth more than 240,000 yuan (39,000 U.S. dollars) to help certain prisoners gain imprisonment remissions.

A police in southwest China's Guizhou Province also accepted 180,000 yuan from prisoners' families for promising to help them gain a commutation or parole.

The recalling came after new rules to tighten the granting of imprisonment remissions for prisoners in April. The rules are aimed to prevent influential criminals from escaping punishment through money and power, as part of China's drive to bring "tigers," referring to corrupted high-level officials, to justice.

The new rules focus on criminals convicted of three types of crimes, abusing power, organizing mafia-style groups and financial fraud, stipulating that a strict court hearing is necessary when these people apply for serving sentence out of prison, a commuted sentence or parole.

According to a prison audit by the SPP, China had a total of 90,925 criminals of the three types by the end of May, including 52,819 of power abuse, 12,507 of mafia-style gang related crimes and 25,599 of financial fraud.

Only 66,718 of them are serving sentence in prisons, while 23,967 are serving in community rehab centers and 240 in detention houses.

The SPP also said it has detected loopholes in judicial supervision in many places.

Some courts do not set an exact timeline for the end of the remission of serving out of jails, and some criminals even did not report to the local community rehab centers, according to the SPP.

When some criminals apply for a bailout with reason of suffering from serious illnesses, the courts do no have an unified and clear standards for the assessment of some illnesses, the SPP said. It suggested authorities should amend relevant rules.

For instance, a former local senior official surnamed Liu was sentenced to death with a reprieve, and then was bailed for treating illnesses. He had then always been outside the jail until this year the local procurators uncovered his case and took him back in prison, the SPP said.