CHONGQING, Nov. 13 (Xinhua) -- China's fourth largest city of Chongqing has joined a list of cities to crackdown on unlicensed cabs in a bid to end the taxi driver strikes that have sprung up around the country.

    The southwestern municipality on Thursday announced a three-month campaign to crack down on unlicensed taxis to placate licensed drivers who stopped work last week.

    The campaign, to be jointly conducted by the transport administration and the police, would start on Friday, said Zhou Bo, spokesman of the municipal government.

    The announcement was made in the wake of the two-day strike last week when disgruntled taxi drivers demanded government action to resolve problems such as high rental fees, fuel shortages, and unlicensed taxis.

    Unlicensed cabs, among other grievances, also sparked strikes in the southern tourist city of Sanya and the northwestern county of Yongdeng earlier this week.

    The local governments have pledged to take measures to protect the interests of licensed drivers.

    Authorities in other cities, such as Beijing and Shenyang, have also staged crackdown campaigns on illegal cabs.

    A small number of cabbies unable to bear the daily loss of about 300 yuan (44 U.S. dollars) in rental fees returned to work in Sanya on Thursday, three days after the strike began.

    The exact number of taxis operating was not available, but catching a taxi is still said to be very difficult.

    More than 100 drivers have been rallying outside the city government offices since Tuesday, demanding a detailed government plan to tackle their complaints.

    Many drivers said they would resume services as long as the companies scrapped rental fees, but they had no indication of this yet.

    Twenty-three of the 28 people detained by police for suspected violence during the strike were still in custody on Thursday, a police source said.