A bomb has exploded in the south-western city of Quetta in the Pakistani province of Balochistan, killing one man, police say.
A December bomb attack in Quetta killed at least 11 people
Reports say the victim was carrying the bomb on a motorbike when it accidentally exploded.
A few hours earlier a bomb exploded near a passing passenger train in the city, injuring four railway workers.
The army has said it will establish three new garrisons in Balochistan to deal with a growing security problem.
The motorcycle bomb went off in a market in Quetta.
"The man who died in the blast was taking the bomb to some area for terrorist activity, but the bomb exploded and he died instantly," Quetta's senior police official, Hamid Shekel said, the Associated Press news agency reports.
Another officer said the dead man had been involved "in previous bomb attacks in Quetta".
The earlier attack took place as the Zaffar Express train was leaving the city. Reports say the bomb was triggered by remote control.
Quetta has been the scene of a number of bomb attacks in recent months. An explosion in December killed 11 people.
A new militant group calling itself the Balochistan Liberation Army (BLA) has claimed responsibility for some of the attacks.
The security situation in Balochistan deteriorated sharply in 2004. Rebels stepped up their attacks, killing more than 30 soldiers and paramilitary personnel.
In January the government opened talks with senior Balochi politicians to end a two-week long stand-off with armed tribesmen around the Sui gas installation.
Armed clashes earlier in the area had disrupted the supply of natural gas to much of the country.
The demands of nationalists and militants include more autonomy for the province and an end to military cantonments and huge development projects that they feel may marginalise the local Baloch population.