Three large explosions shook central Baghdad on Sunday, Reuters witnesses said.
An Interior Ministry source said two were bombs which blew up in the Mansour district of west-central Baghdad, one of them near the German embassy.
Another law enforcement source said the third blast occurred near the Iranian embassy.
There was no immediate word on casualties.
Iraqi authorities had warned of a possible escalation of violence due to rising tensions surrounding a March 7 parliamentary election that produced no clear winner.
On Friday gunmen killed 24 people in a village just south of Baghdad.
(Reporting Muhanad Mohammed, writing by Ian Simpson)