"I work day and night. You'll find me here (in the workshop) anytime from 9:00 am until 4:00 am," Raseel says shyly, as his small hands skillfully work with various car parts.
With an innocent smile never leaving his face, little Anwar closely follows his older brother's moves as he also tries to master the job.
A study carried out in 2010 by the US-based aid group CHF International revealed that out of Yemen's 11 million children, five million are currently employed.
Three-fifths of those do not receive an education while the remaining two million both study and work at the same time.
CHF said that 40 percent of Yemeni children are drawn into the labour market between the ages of seven and 13.
According to the study, 10 percent of the country's children start working when they are nine years old. By the age of 12, the number doubles to 20 percent and reaches 40 percent as they reach 13.
CHF said that 80 percent of those children are involved in hazardous and arduous jobs, while over 60 percent use dangerous tools and over 30 percent said that they were injured or have fallen ill due to their jobs.
Twenty percent of Yemen's working children were physically and emotionally abused, while 10 percent were sexually abused, the study found.
And some parents try to have their children smuggled into neighbouring Saudi Arabia, where they can earn 1500 Saudi Riyals (about 400 dollars) a month -- a large amount compared to salaries in Yemen, according to the study.
Yemeni rights group SEYAJ says hundreds of children in the provinces of Hajja and Al-Hudaydah, in northwest Yemen, were involved in drug trafficking into neighbouring countries.
"There are more than 200 children used in drug trafficking into Saudi Arabia... in return for small amounts of money given to those children," Ahmed al-Qurashi, head of SEYAJ, told AFP.
The Sanaa government is aware of the problem of child labour.
Adel al-Sharaabi, director of social defence at the ministry of social affairs and labour, said "the reason behind child labour is the increase in poverty in the country."
"The only solution to this problem is to improve Yemen's economy," he added.
But with the impoverished country facing a range of severe economic challenges, and struggling to maintain security and political stability as it cracks down on extremist networks, the plight of Yemen's children does not appear to be a high government priority.
A study carried out by the social affairs ministry's child labour unit in June said that "192,000 children are currently working in the farming sector," and that due to the continuous use of pesticides, these children are prone to developing skin rashes, blindness, asthma and bronchitis.
Nearly half of the children working in agriculture suffer from skin infections, while 30 percent complain of mild purulent inflammations and 20 percent face intestinal infections, the government study said.
Fifty thousand work as farmers in Hajja, 38,000 in Ibb, 27,000 in Zamar, 28,000 in Amran, and 20,000 in Al-Hudaydah, it added.
"Agriculture, which was once considered one of the safest jobs, has now become one of the most dangerous due to the poisonous and cancerous pesticides used," Qurashi said.
After farming, auto repair shops employ the largest number of child labourers, according to the government study.
"There is a significant rise in child labour" due to the rise in rates of poverty and unemployment, Qurashi said. In such circumstances, "more children will do any job regardless of how dangerous it is."
Children are also paid to work as "hired fighters" in Yemen's tense north, either to fight with government-backed tribes against Zaidi Shiite rebels or vice-versa, in the rebels' Saada stronghold, Qurashi said.
"The government knows this," he added.
In addition to working from a young age, Yemen's children face dangers from hunger.
"Half of Yemen's children are chronically malnourished and one out of 10 does not live to reach the age of five," according to the World Food Programme.
"Such emergency levels of chronic malnutrition -- or stunting -- are second globally only to Afghanistan, the proportion of underweight children is the third highest in the world after India and Bangladesh," it says.
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