Iraqi police say a bomb blast has killed 72 people in Baghdad, less than a week before U.S. troops are to withdraw from Iraq's urban areas.

More than 160 people were wounded in Wednesday's blast, which tore through a market in the mostly Shi'ite district of Sadr City. Officials say the attacker hid the bomb under a cart of vegetables loaded on a motorcycle.

In other violence, officials say one person was killed and at least 14 wounded in two other attacks in the Iraqi capital.

Just hours before the Sadr City bombing, a U.S. military spokesman noted a declining trend in the number of high-profile attacks in Iraq, with only 10 so far this month, compared to 16 in May and 28 in April. 

U.S. Brigadier General Steve Lanza also said only a small number of U.S. troops will remain in Iraqi cities after a June 30 deadline, but that the exact number was still being worked on. 

U.S. Defense Department spokesman Geoff Morrell said Wednesday a rise in violence is expected as U.S. combat forces prepare to withdraw from Iraq's urban areas.  But he noted the overall security climate is good.

Iraqi Prime Minister Nouri al-Maliki has also warned that insurgents are likely to intensify their strikes.

Earlier this week, a series of attacks in Iraq left dozens dead, and a truck bombing last Saturday near Kirkuk killed almost 70 people.

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