Four explosive devices went off in Colombia late Friday ahead of an Americas summit, without causing any casualties or damage to buildings

Four explosive devices went off in Colombia late Friday ahead of an Americas summit, without causing any casualties or damage to buildings, police said.

The first two crude low-power bombs exploded near the US Embassy in Bogota shortly after the arrival in Colombia of US President Barack Obama, who is due to take part in the summit in the resort city of Cartagena.

"Nobody was killed, nobody was injured, and there was no damage," a police official told AFP on condition of anonymity, without revealing if there were any suspects.

“There are windows broken, but nobody hurt or killed,” a senior police source told Reuters, saying the explosives were placed in a ditch in a residential area near the attorney general’s office.

The incident occurred around 7:30 pm local time (00:30 GMT Saturday), prompting police units to swarm into the area and start investigation.

These explosions were followed by two similar ones in Cartagena, which is hosting the summit.

In addition to the US Embassy, the area in Bogota where the devices exploded is home to some important Colombian government buildings.

The prosecutor general's office is located nearby as well as the so-called National Administrative Center, which houses several government ministries.

The Colombian capital and other major cities have witnessed unrest during the last decades.

According to the AFP, the Revolutionary Armed Forces of Colombia (FARC) has been at war with the Colombian government since 1964 and is believed to have 9,000 fighters in mountainous and jungle areas.