(Updates Mosul death toll)
BAGHDAD, Nov 23 (Reuters) - A bomb hidden in a box of birds killed 13 people and wounded 57 at a popular pet market in central Baghdad on Friday, police and witnesses said, describing the deadliest attack in the Iraqi capital in two months.
Body parts were strewn among bird carcasses as bystanders piled victims into carts and rushed them to ambulances after the blast at the crowded Ghazil pet market. Police said four policemen were among the wounded.
The market attack was the worst since 32 people were killed by twin car bombs in the predominantly Shi'ite district of Bayaa in southwestern Baghdad on Sept. 26, and could dent new-found confidence among Iraqis that security is getting better.
In the northern city of Mosul, two separate bombings killed nine people, including six policemen, police said.
A suicide car bomb targeting a police patrol killed five people in southeastern Mosul, said Brigadier-General Mohammad al-Wagaa, head of the Mosul police operations room. A second in the same area killed four people.
Levels of violence have fallen across Iraq in recent months, with the U.S. military saying attacks were down by 55 percent since an extra 30,000 U.S. troops became fully deployed in mid-June.
With the lull in bloodshed, something approaching normal life has started to return to Baghdad. Thousands of Iraqis have also been returning home after fleeing the violence.
People have been going to markets and restaurants at night, unheard of at the height of the violence after the bombing of a revered Shi'ite shrine in Samarra in February 2006 unleashed waves of sectarian killings.
"The people were happy the last two weeks because the situation has improved. This explosion disturbs us," said Ghazil stallholder Mohammed Abu Salim.
The pet market, a popular weekend spectacle, sells a colourful range of creatures from guard dogs and monkeys to parrots, pigeons and tropical fish.
It has been targeted several times in the past. Seven people were killed there in a blast in January. A month earlier, three people were killed in another attack.
STAINED WITH BLOOD
Bystanders and stallholders covered their noses with masks because of the stench after the bombing. Salim said police fired into the air after the blast.
"We expected another explosion so we all ran away," he told Reuters. "Then we went back to evacuate the wounded. I saw someone at a sandwich booth, he was burned completely, smoke was coming from his body. Another person lost both his legs."
Another witness, who did not give his name, said the bomb went off at about 9 a.m. (0600 GMT) and had been hidden in a box used to keep birds sold at the market. He said he had helped remove about a dozen bodies.
"I have already changed my clothes, they were stained with blood," he said.
The increase in U.S. troops has targeted Shi'ite militias and al Qaeda fighters who are blamed for most large-scale bombings in Iraq. U.S. commanders, however, say that overall levels of violence in Iraq remain too high.
On Thursday, 10 mortar bombs landed in Baghdad's Green Zone, the heavily fortified central Baghdad compound which houses the U.S. embassy and the Iraqi parliament, in an attack coinciding with the U.S. Thanksgiving holiday.
The growing use of neighbourhood police units, organised by mainly Sunni Arab tribal sheikhs, has also been credited with playing a part in bringing violence levels down.
But the neighbourhood police units, organised by "Awakening Councils" of tribal leaders, have also become targets for attacks in recent weeks.
Police said al Qaeda militants killed eight members of a neighbourhood police patrol on Thursday in Baghdad, raking them with heavy machinegun fire from a stolen Iraqi army vehicle. (Editing by Dean Yates and Michael Winfrey)
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