Health officials have detected over 10 people with the UK variant of the coronavirus.
"But the number may change tomorrow," said Prof Tahmina Shirin, director of the Institute of Epidemiology, Disease Control and Research.
The cases have been detected through genome sequencing, she told The Daily Star.
Tahmina added that she would not say the highly contagious UK variant has spread across the country and also would not attribute the recent surge in new cases to the UK variant.
Researchers are working to expand the number of genome sequencing to find out more cases, she said.
"Genome sequencing is a continuous process and we are doing it regularly to find out more cases," she added.
The director did not say how much genome sequencing has already been done.
"The variant has slowly mutated from time to time. We are also looking into the mutated ones."
The UK variant of coronavirus, also known as N501Y.V1, was detected in Bangladesh on January 5.
The person diagnosed with the strain had travelled to the country from the UK. Similar cases were found in Dhaka and Sylhet later.
But the Director General of Health Services (DGHS) did not reveal the matter until The Daily Star reported about it on March 10.
Experts fear that the UK variant could be one of the reasons behind the sudden rise in new cases and deaths in the country.
"The number of genome sequencing is very limited here because it's expensive. More genome sequencing is needed to know how far the UK variant has spread in the country," Prof Md Sayedur Rahman, chairman of pharmacology at the Bangabandhu Sheikh Mujib Medical University (BSMMU), told The Daily Star yesterday.
The government has to make special budget allocation and engage capable laboratories to make the process faster, he said.
People's reluctance to follow the health guidelines and a widespread misconception that vaccination means protection are also reasons why the virus has been spreading, he added.
"We are observing the rise in positivity rate, hospital admission and death rate. We have to expand the genome sequencing facilities and the antibody tests to see how the vaccine is working."
DGHS officials also said people dropping their guards after a steep decline in new cases are the reason behind the recent spike.
"We have not found any link between the UK variant and the sudden rise in infection. Rather, it is the carelessness of the people about maintaining health guidelines that contributed to the rise," Tahmina said.
According to the World Health Organization, 83 countries have reported cases of the UK variant.
Scientists say the UK variant may be up to 70 percent deadlier than the previous strains. Detected in September for the first time, it quickly became the dominant variant in the UK, said a UK government report in February.
India says it has found 242 cases of three variants -- mostly the UK one -- in the population, BBC reported earlier this month.
A New York Times report in late February said British scientists were increasingly finding the UK variant to be linked to a higher risk of death.
It also said the UK variant is linked to an increased need for hospitalisation.
Scientists estimate that the variant was being transmitted 35 to 45 percent more easily than other variants in the US, the report said.