Co-ordinated blasts

Five bomb-laden vehicles were driven into a finance ministry office, a tunnel leading to the labour ministry, a courthouse, a police patrol, and interior ministry offices in central Baghdad.

There was no immediate claim of responsibility, but Iraqi officials said the attacks bore the hallmarks of al-Qaeda and fighters loyal to Saddam Hussein's Baath party who plunged the country into sectarian bloodshed and chaos in 2006-2007.

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The last two major strikes on Iraqi government sites were co-ordinated blasts in August and October this year that killed more than 255 people.

http://english.aljazeera.net/news/middleeast/2009/12/20091292225414390.html

Could you please explain to me what "co-ordinated blasts" means in this context?