Saturday's fatal explosions in Bangladesh appear to be part of a rising trend of bomb blasts over the past five years, which have left more than 100 people dead.
Most of the cases remain unsolved with police having few leads on who carry out the attacks, or their motives.
Bomb blasts are in a range of cities and cover a range of targets
This year alone bombings have ranged from Sylhet in the north-east to the capital, Dhaka, to Khulna in the south-west.
The targets are just as varied - cinemas, newspaper editors, political rallies, even the British high commissioner.
The most recent explosions have targeted the leading opposition Awami League.
Saturday's blasts echoed a bomb attack in Sylhet on 7 August which the city's mayor, Badruddin Kamran, said was an attempt to assassinate him.
He was meeting Awami League members and the one fatality in the explosion was an Awami League supporter.
British High Commissioner Anwar Choudhury was a target
At least 30 people were wounded in the car bombing.
Mr Kamran said he had received a threatening letter from a previously unknown group calling itself the "Tiger Killing Force".
The political blasts come against a backdrop of increasing acrimony between the Awami League of Sheikh Hasina Wajed and the Bangladesh Nationalist Party-led government of Begum Khaleda Zia.
A series of Awami League-led strikes and protests in April and May led to a government clampdown that saw the arrest of about 7,000 opposition supporters in Dhaka.
The authorities defended the mass arrests as the best way of foiling a conspiracy against the government.
The opposition was trying to force the government, which it accuses of being inefficient and corrupt, to call early elections.
The government says it intends to stay in office until 2006, when the next elections are due in the country.
Further violence erupted on 7 May with the assassination by unknown gunmen of senior Awami League MP Ahsan Ullah Master in Tongi, 20km (12.5 miles) north of Dhaka.
But the Awami League has not been the only target.
Awami League supporters show rising acrimony with the government
On 6 August blasts outside two busy cinemas in Sylhet killed one person and injured seven others.
In May, the British High Commissioner, Anwar Choudhury, was injured in a bomb attack on a Muslim shrine in Sylhet which left three dead.
Following that explosion, British detectives from Scotland Yard visited the city to investigate but no breakthrough has been announced.
A blast at the same shrine, of Muslim saint Hazrat Shahjalal, in January this year killed three people.
Two leading journalists have also been killed in bomb attacks this year.
Humayun Kabir, editor of the Bengali daily, Janmabhumi, died in Khulna in June.
In January, senior journalist Manik Saha, a regular contributor to the BBC Bengali service, was killed in a similar bomb attack in Khulna.