Iraqi police say at least six people have been killed and 54 wounded in separate bomb explosions in Baghdad.

Police say four people died and 50 were wounded Friday by back-to-back explosions in one of the capital's historic markets Ghazil.

Shortly afterwards, a roadside bomb exploded in an eastern neighborhood, killing two people and wounding four others.

In the southern city of Basra, Iraqi security forces have set up roadblocks to enforce a month-long state of emergency declared by Prime Minister Nouri al-Maliki. He called for the state of emergency Wednesday, vowing to crack down with an "iron fist" on gangs behind rampant violence in Basra - the center of the country's oil trade.

In another development, British television aired video footage Thursday of several dead adults and children Iraqi police say were among 11 civilians shot dead by U.S. troops in the town of Ishaqi in March.

BBC reported U.S. officials said at the time that four people died during a military operation in the town (about 100 kilometers north of Baghdad). The BBC said it obtained the video from a Sunni group opposed to coalition forces.

The video release comes as the U.S. military investigates whether U.S. Marines intentionally killed as many as 24 unarmed Iraqi civilians last year in the town of Haditha.

On Thursday, the U.S. military in Iraq ordered American commanders to conduct core values training on legal, moral and ethical standards on the battlefield. President Bush says he is concerned by the Haditha allegations, and promised a full and complete investigation.

Some information for this report was provided by AFP, AP and Reuters.