Fighting between ethnic Armenian and Azeri forces over the Nagorno-Karabakh region erupted on Sept. 27 and has since escalated to its deadliest level since the 1990s.

The clashes have not affected energy supplies from the region but have put energy markets on edge.

Azerbaijan said late on Tuesday that it thwarted missile attacks in the vicinity of the oil pipelines including the BTC, which accounts for about 80% of Azeri oil pipeline exports, carrying more than 500,000 barrels of oil per day.

Armenia has denied it targeted the energy infrastructure.

"We are especially worried about yesterday's reports of a missile attack, which was intercepted and destroyed by Azerbaijan's air defence systems in the vicinity of BTC and SCP (South Caucasus Pipeline) export pipelines," BP said in a statement.

"While the security of all assets which BP operates on behalf of the Azerbaijan government and our partners is provided by the Azerbaijani government, we continue to work closely with the relevant authorities in an effort to take necessary measures to provide the protection of our personnel, operations and assets."

(Reporting by Gabrielle Tétrault-Farber in Moscow, Nailia Bagirova in Baku and Nvard Hovhannisyan in Yerevan; Writing by Alexander Marrow and Vladimir Soldatkin; Editing by David Goodman)