PRAGUE, Czech Republic — Former Czech President Vaclav Havel was in serious but stable condition Wednesday, two days after undergoing minor surgery on his throat, a team of medical specialists said.

Dr Martina Pelichovska said the former president's condition worsened Tuesday and again early Wednesday when the bottom of his right lung became clogged with phlegm.

"It led to significant problems with breathing, Pelichovska said.

Havel has suffered from this problem before, doctors said. He is being treated at the department of anesthesiology and resuscitation of Prague's Motol hospital.

Pelichovska said Havel is being treated with antibiotics and has a mask that makes it easier for him to breath.

She said Havel is not in pain and "cooperates well" with his doctors.

"His condition is serious," she said. "At the moment, he is in stable condition and his life is not threatened."

Pelichovska said doctors fear that inflammation could develop in Havel's right lung and spread to the left one, "which would seriously influence his ability to breath." She refused to give any prognosis.

Jan Betka, a surgeon who successfully operated Monday on a small abscess that had been making it difficult for Havel to swallow and breathe, said doctors had not expected the postoperative recovery to be easy.

Havel "is a complicated patient," Betka said.

Betka said the complication developed because Havel in the past has undergone a number of other operations on his lungs.

The 14-member medical team plans to meet daily to asses Havel's condition, Dr Martin Holcat, the team's head said. Havel was hospitalized Monday.

Havel, a former chain smoker, has a history of respiratory problems dating to his years in communist jails, and has been hospitalized repeatedly in recent years. He has suffered chronic bronchitis since a third of his right lung was removed in December 1996 following the discovery of a cancerous tumor.

A year ago, he was treated for an irregular heartbeat at the IKEM hospital in Prague.

Havel was a dissident playwright when he led the 1989 revolution that peacefully toppled communism. He became president of Czechoslovakia in December 1989 and served as Czech president from January 1993 after the country split into the Czech Republic and Slovakia. His last term in office ended in 2003.

Czech Prime Minister Mirek Topolanek wished Havel quick recovery during an address to the European Parliament in Strasbourg, France. The Czech Republic currently holds the rotating EU presidency.