Crude production in Colombia fell 6.4 percent in September, a decline the new mines and energy minister attributed to strikes by workers at oil fields and guerrilla attacks on pipelines.

Mauricio Cardenas, who was named to his post on Sept. 20 after Carlos Rodado resigned, told reporters that crude production in September averaged 891,161 barrels per day, compared with 952,000 bpd a month earlier.

Workers at fields being developed by Canadian-owned Petrominerales and Pacific Rubiales Energy have been protesting - sometimes violently - since mid-July to demand improved working conditions.

In comments to the El Espectador daily, Cardenas referred to last month's strike at the Rubiales field, located in the eastern province of Meta.

He said the incidents once again show "how disruptive it is for the country, its economy and the population for there to be violent actions that interrupt production."

Cardenas added that the decline in output has led to lower royalty payments by the companies.

The impact has been especially felt in Meta province because the shortfall is around $10 million, which translates into fewer benefits for the population, the minister said.

Cardenas also expressed concern over attacks on the Caño Limon-Coveñas pipeline by guerrilla groups, noting that they have repeatedly sought to sabotage it since its inauguration in 1986 and that the National Liberation Army, or ELN, at one point declared it a "military target."

The Mines and Energy Ministry said in a statement that, despite the drop in average daily output in September relative to the previous month, production was still up 11.4 percent compared to the September 2010 level of 800,000 bpd.

Separately, an average of 1.06 billion cubic feet per day of natural gas was sold in Colombia in September, down slightly from an average of 1.07 billion cfd in August.