In a blistering report, the Organization for Security and Cooperation in Europe (OSCE) on Monday said the Turkish election campaign was marked by a "challenging security environment" and restrictions on media freedom.

Sunday's vote brought the ruling Justice and Development Party (AKP) a majority in parliament, after the party had failed to win a majority for the first time in 13 years in June elections.

The intervening five months saw an uptick in violence as a two-year ceasefire between the Turkish state and Kurdish militants (PKK) broke down, furthering polarizing the country along ethnic and ideological lines.

The resumption of conflict triggered bitter attacks in pro-AKP media against the People's Democratic Party (HDP) after the pro-Kurdish party entered parliament for the first time in the June elections, as well as far-right mob violence against the party and the arrest of supporters.

The OSCE said the "challenging security environment, in particular in the south-east, coupled with a high number of violent incidents, including attacks against party members and campaign staff, as well as on party premises, hindered contestants' ability to campaign freely."

The OSCE added that in the two weeks leading up to Sunday's vote, there was "an increased number of attacks against and arrests of members and activists, predominantly from the People's Democratic Party (HDP)."

Campaigning was also impacted by the imposition of special security zones and curfews in several cities in the largely Kurdish populated southeast of the country, the OSCE said.

A double suicide bombing at a peace rally in Ankara in October, which killed more than 100 people, largely from the HDP, also "significantly affected the atmosphere and conduct of campaign," the OSCE said.

The HDP was still able to gain enough votes to get over the 10 percent election threshold to enter parliament, obtaining 59 seats with 10.75 percent of the vote compared to 13 percent and 80 seats in June.

Media under continued pressure

The OSCE said the media environment in Turkey remains "an area of serious concern" as voters' access to different opinions was restricted and pro-government bias prevailed in the media.

"Criminal investigations of journalists and media outlets for support of terrorism and defamation of the president, the blocking of websites, as well as the removal of several television stations from digital service providers and the effective seizure of some prominent media outlets reduced voters' access to a plurality of views and information," the OSCE said.

Most Turkish media outlets are tied to larger holding groups, and as a result "media owners' business interests in obtaining public tenders and state advertising led to interference into editorial autonomy and resulted in limited criticism of the government, in particular on television," the OSCE said.

Highlighting the clampdown on media, days before the election the state confiscated two opposition media outlets and turned them into pro-government mouthpieces.

The OSCE also found the public broadcaster was biased in favor of the government.