Prague  - Former Czech president and playwright Vaclav Havel, an icon of anti-communist resistance, has been treated in a Prague hospital with "an inflammatory illness," his office said Tuesday.

Havel underwent an operation at hospital's otorhinolaryngology clinic, hospital spokeswoman Eva Jurinova said. She said his condition was "stabilized, nevertheless serious."

Neither the hospital, to which Havel was admitted Monday, nor Havel's office would provide further details.

Havel, 72, was last hospitalized a year ago with acute bronchitis and a heart arrhythmia.

Once an avid smoker, he has frequently suffered from serious health problems, including lung cancer, during and after his term as president between 1989 and 2003.

Since leaving office he has advocated human rights and returned to writing for the theater. dpa