Saleha Begum touches the burnt skin on the face of her 23-year-old son and again bursts into tears.

Ever since she came to the burns ward of Dhaka Medical College Hospital, Bangladesh's biggest, she has been unable to stop crying and constantly curses herself.

She said it was her "grave sin" and "greed" that prompted her to send her son out to buy a chicken and the 23-year-old street hawker defied an opposition transport blockade to make his mother happy.

Riyad, who uses one name, was the victim of violence that has left dozens dead in Bangladesh since late October, when an 18-party opposition movement led by former prime minister Khaleda Zia launched a wave of protests calling on her bitter rival Prime Minister Sheikh Hasina to resign ahead of national elections in January.

"There has been no supply of chicken in our market. I asked Riyad to buy one for the family from another market. It has been weeks we haven't eaten a chicken," Begum said, wiping away more tears.

"Little did I know that he would take a bus to go to Karwanbazar to buy that bloody chicken."

Riyad did not complete the journey. Two suspected opposition supporters threw a petrol bomb into the bus on November 29, burning him and 17 other people. Three of those have already died and others are fighting for their lives.

At the crowded and filthy DMCH Burn Unit, where overwhelmed nurses are working 12-16 hours a day, Riyad was one of more than 120 victims being treated, with many battling life-threatening injuries.

With 20 percent or more of their bodies burnt, the bandaged patients are the living reminders of the costly toll of Bangladesh's increasingly deadly politics.

An election in doubt

Hasina and Zia, known as the battling Begums -- Begum is a Muslim honorific -- have alternated power in the impoverished country since 1991. But their latest battle has left the country on the brink.

The opposition wants the return of a "caretaker system" under which a neutral government took over during an election period -- used successfully in the coup-plagued country four times in the past 20 years.

Hasina scrapped it in 2011 and instead in November formed a multi-party interim cabinet -- comprising her allies -- to oversee the general election on January 5, leading to fears among the opposition that she will use her influence to rig the result.

At least 67 people have died in the clashes -- mostly from police firing -- as opposition activists have targeted buses, cars and trains to enforce transport strikes.

On Wednesday, suspected opposition activists derailed a train by removing metal links holding the tracks together, killing at least three people and injuring dozens.

"Whatever their differences, political leaders on both sides must halt their destructive brinkmanship, which is pushing Bangladesh dangerously close to a major crisis," UN rights chief Navi Pillay said at the weekend.

The poor suffer

Businessmen, office workers and government officials have mostly been unaffected by the violence while farmers and small traders have borne the brunt.

In recent weeks, farmers in northern Bangladesh have emptied their milk pots into rivers and ponds because no transport is available to carry their produce to cities.

Hawkers who usually clog almost every street in Bangladesh's busy capital are the worst-hit. They cannot sell goods out of fear of attacks by opposition activists or being caught in police crossfire.

After his savings ran out last week, Mohammad Rubel Mia, an auto-rickshaw driver, finally summoned up enough courage to bring his vehicle out on the street in the eastern city of Comilla.

Protesters stopped his vehicle, overturned it and torched it while Mia, 35, was still inside.

A quarter of his body was burnt and the doctors in Comilla clinic sent him to the DMCH unit for better treatment. "I don't know who is going to feed my two sons and a daughter," a bandaged Mia said in a faint voice.

Lying on the next bed is Abdul Aziz, 35, whom doctors say faces a battle to survive. His vehicle was hit by a petrol bomb thrown by protesters in the port city of Chittagong.

"I don't blame anyone other than our luck. It's our luck that made us born in this land," Aziz mumbled as doctors inserted a feeding pipe in his nose.

Prime Minister Hasina visited the ward on Sunday to highlight the expensive toll of the "opposition's violent politics".

But instead of managing to score political points, she was given a hostile welcome from one of the patients, reflecting the anger of many people who feel they are victims of Bangladesh's violent politics.

When Hasina came to her bed, Geeta Sen, a housewife who was among the 18 people badly burnt in the bus-torching incident, lashed out at her, paying scant notice to the security officers surrounding the premier.

"Our husbands earn food for us. Please don't play with our lives," Sen, 42, whose daughter was also burnt in the attack, was quoted as saying in a local newspaper. She confirmed the quotes to AFP.

"Please be united and protect us. We want a good government, not a sick government," she added.