DUBAI: Iran believes BP operated Azeri oil platforms have polluted the Caspian Sea and may sue the UK oil major if it continues, Iran's Deputy Head of Department of Environment (DoE) has been reported as saying by Iranian media this week.

BP operates the Azeri-Chirag-Gunashli (AGC) oil field and Shah Deniz gas field in the Caspian, which lies to the north of Iran, on behalf of the Azeri government with state energy company Socar.

Iranian officials have complained that Azeri oil has washed up on Iranian beaches over the last year, with Iran's Press TV reporting on Sunday that Iran may sue Azerbaijan.

Mehr news reported on Tuesday that deputy DoE chief Abdolreza Karbasi accused BP of dumping oil waste into the Caspian Sea and that Iran might target BP in court if it continued.

"Last year, southern coasts of the Caspian Sea were covered with oily patches, and in the last such case, four months ago, 25 tons were cleared from Iranian coasts," Karbasi was quoted by Mehr as saying.

He did not say which court Iran might try to sue BP in.

A spokesman for BP said the company had committed to officially report any leaks in the Caspian and had not had to for years.

"We are a responsible operator in the Caspian and as such we have rigorous HSE (Health, Safety, Environment) processes and procedures in place in line with international standards," BP said in an emailed statement on Tuesday.

Last October, Azeri president Ilham Aliyev attacked BP - the biggest foreign investor in Azerbaijan - over declining output from the AGC fields in the last few years.

BP's partners on the AGC project include Exxon Mobil , Chevron and Statoil.