MOSCOW- Russian oil producer Lukoil's trading arm Litasco is increasing purchases from Saudi Arabia, Interfax news agency cited the company's chief executive as saying on Tuesday.

Lukoil and Saudi Aramco are discussing making joint investments in third countries, Vagit Alekperov, Lukoil's head, was also quoted as saying.

(Reporting by Vladimir Soldatkin; writing by Tom Balmforth; Editing by Jan Harvey) ((Tom.Balmforth@thomsonreuters.com;))