Baghdad (AsiaNews/Agencies) - Three car bombs exploded just minutes apart at a busy Baghdad bus station and a nearby hospital during morning rush-hour Wednesday, ripping through buses and killing at least 43 people. Iraqi authorities said the bombings were aimed at terrorising people and triggering a collapse of the government. The attacks came two days after politicians failed to draft a new constitution because of sharp differences on key issues, raising concerns of fresh political turmoil.

Two car bombs exploded 10 minutes apart at the bus station in the central district of Al-Nahda and a third exploded near Al-Kindi hospital in the same neighbourhood.

At least 43 people were killed and another 76 wounded.

One of the bombs at the Al-Nahda bus station left a two-metre wide crater on the road. At least three buses were gutted by fire. The vehicles would have been packed with passengers at the time of the explosion. Al-Nahda is a major bus station which links the capital with the predominantly Shiite regions to the south of Baghdad.

The third car bomb exploded in a leafy part of the neighbourhood where people usually seek shade in the blazing heat of Baghdad's summer, especially during the rush-hour.

The bombings seemed clearly aimed at killing as many civilians as possible. Most rebel attacks usually target Iraq's fledgling security forces.

Al-Qaeda has issued a number of Internet threats against those who plan to participate in a scheduled referendum on a constitution in mid-October.

"One aim of the bombers is to put fear in the hearts of Iraqi people and the other intention is to trigger a government collapse," government spokesman Leith Kubba said on state-owned Iraqia television.

Wednesday's bombings occurred after attempts to write the country's first post-Saddam Hussein constitution by a Monday deadline failed, prompting parliament to give politicians another week to complete the charter.

"This is a one-time extension... if Iraq misses the next deadline, we have to dissolve the national assembly, the government will collapse and fresh elections will have to be held," Munther al-Fadhal, a member of the constitution panel said.

Prime Minister Ibrahim Jaafari and other politicians downplayed the crisis.

"The demography of Iraq and its complicated political map" should be taken into consideration, Jaafari said. "The delay was for one week only and the pending points do not need a longer period."

But politicians spoke of intractable differences between the Sunni, Shiite and Kurdish representatives battling to hammer out an agreement by the new August 22 deadline.

"There are serious differences on issues like the sharing of national (oil) wealth and the demand of self-determination from the Kurds," Fadhal added.

The drafting of the constitution, due to be put to a referendum in October, is a key phase in Iraq's political transition which the United States and its allies hope could pave the way to a pullout of foreign troops.

Shiite panelist Jawad al-Maliki said on Tuesday he was optimistic an agreement would be reached, but indicated a draft might be presented without all parties on board.

"We are not seeking 100 percent consensus -- the most important thing is that the people of Iraq accept (the constitution) in a referendum."