Bangkok, virtually unrecognizable after four days of clashes, braced itself for more unrest Monday after doctors announced the death of a key anti-government leader who was wounded by a sniper`s bullet last week, according to CNN.

Maj. Gen. Khattiya Sawasdipol -- a renegade general better known as Seh Daeng, which means Red Commander -- died at 9:20 a.m. Monday (10:20 p.m. Sunday ET), Vachira Hospital officials told CNN.

At least 35 others have died in the bitter standoff between anti-government protesters and troops since Thursday, with 11 of those deaths occurring in sporadic fighting throughout Sunday and overnight. At least one of the fatalities was a soldier, the Erawan Emergency Center said Monday.

"We`re very concerned about these rapidly climbing casualties," said Phil Robertson, deputy director of the Asia division of Human Rights Watch.

The organization is calling on militant groups among the anti-government protesters to stop using violence and on the government to follow U.N. principles on use of force and firearms, Robertson said. He said violence in densely populated neighborhoods is placing innocent civilians at risk.

"We`re very concerned that both of the sides, both the army and the Red Shirts, are in denial and digging in, and we think this is very dangerous," Robertson said.

The government ordered schools and offices closed Monday and Tuesday "in order to ensure the safety of the public" after the protests paralyzed the city center.

At least nine international embassies in Bangkok -- the U.S., British, Belgium, Canadian, German, Japanese, New Zealand, Swedish and Australian embassies -- said they will remain closed until Tuesday at the earliest as a result of the clashes.

Meanwhile, an "intense and fierce" gunbattle broke out late Sunday in the city`s Lumpini Park, where anti-government protesters have amassed by the thousands. It was unclear whether the shooting came from the Thai military or the protesters.

The battle came hours after the Thai government called on the protesters to stop the violence but stopped short of agreeing to a demand that the United Nations mediate between the parties.

A group of doctors were traveling to a Buddhist temple Monday to provide medical care to women and children who have taken shelter there, a spokesman for the Royal Thai Police said.

The government extended its state of emergency to five more provinces, bringing the total to 22 provinces along with the Bangkok metropolitan area, spokesman Panitan Wattanayagorn said in a televised news conference.

The provinces mainly are in north and northeastern Thailand, where the anti-government Red Shirts` strongholds are located. The government has also banned financial transactions with 106 companies and individuals over the protests, Panitan said.

Throughout the day Sunday, black smoke billowed and gunshots rang out in the capital`s streets, which have turned into battle zones during the bitter standoff. Nearly 240 people have been injured in the clashes since Thursday, emergency officials said.