Istanbul - A publishing group that has clashed repeatedly with the party of Turkish Prime Minister Recep Tayyip Erdogan is being investigated for violating fair competition practices, government officials announced Friday.

The Dogan group, which publishes Hurriyet and the English-language Daily News, is being reviewed to see if its advertising practices comply with competition policies, reported the agency in charge of competition oversight.

Dogan Yayin Holding is Turkey's leading media group, with sales of about 1.5 billion euros (2.2 billion dollars) and 13,000 employees.

However, the group is also in a prolonged conflict with Erdogan's government, after publications owned by the group reported last year on charges of corruption and a spending scandal within Erdogan's Justice and Development Party.

Most recently, tax authorities hit the group with a fine of 1.7 billion euros for irregularities in the sale of parts of the group to the German media group Axel Springer.

International organizations have decried the ongoing fight as a blow to press freedom. Erdogan has criticized the groups' publications several times and urged his supporters to boycott its newspapers. (dpa)