Bangkok, Thailand (CNN) -- Protesters and security forces continued to clash on the streets of Bangkok Monday as thousands of anti-government demonstrators defied a deadline to end their occupation of central areas of the city.
Around 5,000 protesters are still on the streets following days of violent unrest in which at least 35 people have died since Thursday, including a key anti-government leader who was critically wounded by a sniper's bullet last week.
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.
Thai government spokesman Panitan Wattanayagorn said the government's objective was to protect civilians caught in the crossfire.
"Our objective is to secure the area, to prevent the elements that have weapons of war to attack the officers and attack the people," said Panitan. "We are communicating to the protestors for them to know that they will all be transported back home safely," he said.
An airplane circling the demonstration area and a televised warning broadcast multiple times Monday ordered protesters to vacate the streets immediately.
The announcement said those who did not leave by 3 p.m. (4 a.m. ET) would face a maximum sentence of two year's imprisonment for violating the order. Government officials have not said what they plan to do now that the deadline has passed.
Leaders of the anti-government United Front for Democracy Against Dictatorship (UDD) told CNN's Sara Sidner Monday that they were resolute in their determination to stay in the area but said they were ready to negotiate immediately if the government agreed to U.N.-mediated talks.
Thousands of anti-government protesters, known as "Red Shirts," have occupied areas of downtown Bangkok for weeks, calling for Thai Prime Minister Abhisit Vejjajiva to call new elections. The Red Shirts support former Prime Minister Thaksin Shinawatra, who was ousted in a 2006 bloodless military coup.
But the standoff erupted into street battles last week as the government deployed security forces to disperse the protesters.
Eleven people were killed in sporadic fighting throughout Sunday and overnight, while at least 240 people have been injured since Thursday. At least one of the fatalities on Sunday was a soldier, the Erawan Emergency Center said Monday.
Members of a radical faction that Khattiya headed told CNN they observed a three-minute silence when his death was announced Monday. Some were in tears as they described him. But it was unclear whether his death would spark more violence or dampen their resolve.
Phil Robertson, deputy director of the Asia division of Human Rights Watch, called on militant groups among the anti-government protesters to stop using violence, and calling on the government to follow U.N. principles on use of force and firearms. He said violence in densely populated neighborhoods is placing innocent civilians at risk.
"We're very concerned about these rapidly climbing casualties," Robertson told CNN. "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."
But neither side showed signs of pulling back Monday, as black plumes of smoke filled the air and the sound of gunshots continued to echo through the capital's streets.
Supatra Jenstitvong-Assavasukee said the violence has forced her manufacturing and trade business to move meetings with clients to the outskirts of the city, shut down her son's school and stopped her from shopping downtown.
"Everyone hopes for it to be over really soon. It's really destroying a lot of things," she said.
Beth Saengow, a school administrator who lives in Bangkok, said it seems like the violence is escalating.
"Usually Thailand is a peaceful country ... I'm sure it will affect the tourism. I'm just worried about the economy," she said.
At least nine international embassies in Bangkok -- the U.S., British, Belgian, 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.
The government has declared a state of emergency in 22 provinces along with the Bangkok metropolitan area, Panitan said. It has also banned financial transactions with 106 companies and individuals over the protests, he said.
"The government has been under pressure to be more decisive in its action," a senior Thai government official told CNN. "We have been showing patience and restraint." That, he said, has upset those who want the government to take action against the protesters.