A series of explosions rocked Assam Wednesday, killing a policeman and damaging several vital installations, including a crude oil pipeline, officials said. 

In the western district of Bongaigaon, a policeman was killed and four more were wounded when a bomb planted in a market went off as a police team was trying to defuse it.

A police spokesman said there were nine explosions in different parts of the state. Three blasts occurred in the main city of Guwahati, including one at the international airport.

The spokesman said a powerful landmine blew up a crude oil pipeline near Lankachi village in eastern Assam's Tinsukia district, 550 km from Guwahati. The blast occurred at 8.50 p.m.

"There was a big fire in the area after the blast. Fire tenders were rushed to the location," a senior police official said on telephone from Tinsukia.

The pipeline belongs to Oil India Limited (OIL), India's premier oil exploration firm. 

"We have suspended transportation of crude oil as a precautionary measure," an OIL official said. 

"The three blasts in Guwahati took place between 7 p.m. and 8 p.m. - one exploded outside a local police station, another near a hospital and the third outside the Gopinath Bordoloi International Airport," the spokesman said.

"Fortunately the explosions missed the targets as there were no people at that time."

The blast at the airport damaged a part of the wall in the parking lot though no one was hurt. 

Chief Minister Tarun Gogoi blamed all the blasts on the outlawed United Liberation Front of Asom (ULFA), which is fighting for an independent homeland in Assam since 1979.

"We have intelligence reports that the ULFA was planning an attack ahead of their 'military raising day' on March 16," Gogoi said. 

There were also three explosions in eastern Assam's Sivasagar district.

"Three bombs planted beneath a transmission tower went off damaging the power installation," said district police chief Debojit Hazarika. 

Another blast in eastern Assam's Nagaon district damaged a telephone exchange.