BAGHDAD, Dec 8, 2009 (AFP) - Central Baghdad was rocked by three massive explosions in quick succession on Tuesday, causing large plumes of smoke to rise into the air, an AFP correspondent witnessed.

The first explosion was heard at 10.25 am (0725 GMT) with a second blast within seconds and a third one minute later.

Sporadic gunfire then sounded and the sirens of emergency vehicles were also heard.

Violence across Iraq dropped dramatically last month, with the fewest deaths in attacks since the US-led invasion of 2003. Official figures showed a total of 122 people were killed in November.

However the Baghdad government and the US military have warned of a rise in attacks in the run up to a general election expected to take place in February.

The threat of political violence linked to the election is a major concern for the Iraqi government and US forces after bloody attacks in Baghdad in August and October that killed more than 250 people.

The attacks, including truck bombings outside the finance, foreign and justice ministries, punctured confidence in the Iraqi security forces.

"We believe that there will be an attempt to conduct more attacks between now and the election," General Ray Odierno, the top US commander in Iraq, said in November.