By Daren Butler and Ayla Jean Yackley
ISTANBUL/DIYARBAKIR, Turkey (Reuters) - A far leftist group claimed responsibility on Wednesday for bomb and missile attacks on Turkish government and ruling party offices overnight and poured scorn on a budding peace process with Kurdish militants.
The Revolutionary People's Liberation Party-Front (DHKP-C) said its members attacked the Justice Ministry and offices of the ruling AK Party with hand grenades and a shoulder-fired missile in the capital Ankara late on Tuesday.
"The AKP rules the people with police and judicial terror ... To those who constantly enforce terror, the people's justice will one day knock on your door," a statement posted on a website close to the DHKP-C said.
The blasts preceded an anticipated ceasefire call on Thursday by jailed Kurdish militant leader Abdullah Ocalan. He has been negotiating with state officials on an end to a 29-year conflict that has killed 40,000 people, limited economic growth and undermined Turkey's bid for European Union membership.
The truce call, expected to coincide with the Kurdish New Year, would be a big step in what is shaping up to be the most serious effort yet to end the bloodshed with Ocalan's Kurdistan Workers Party (PKK) militants.
The struggle with the PKK, deemed a terrorist group by the United States and the European Union as well as Ankara, is Turkey's primary domestic security concern and there are forces on both sides opposed to a resolution.
The DHKP-C and PKK were both formed in the 1970s with similar leftist ideologies, although the former pursued a virulently anti-American and anti-imperialist path while the latter focused on Kurdish identity.
The two have cooperated in the past and the DHKP-C would have little to gain from a peace settlement between Turkey and the PKK.
"Who are you deceiving? What 'settlement', what 'peace' are you talking about in our country where the people are woken daily by (police) operations?" the DHKP-C statement said.
Turkish police have detained more than 100 people in a series of operations against the DHKP-C since January, most recently seizing 12 people on Tuesday.
In Diyarbakir, the largest city in the mainly Kurdish southeast, the region's main pro-Kurdish party was making final preparations for the Kurdish New Year "Newroz" celebrations which tens of thousands of people were expected to attend.
"We will fulfil properly every duty which our leader (Ocalan) gives to us," the PKK said in a statement to mark the celebrations. But it complained that Turkey's armed forces had bombarded areas where PKK fighters are located in northern Iraq on Tuesday with artillery shells and mortar bombs.
The DHKP-C has carried out retaliatory attacks before for arrests of its members and has become more prominent in recent months as the PKK peace process has advanced.
Early on Wednesday, a small bomb exploded near state offices in Istanbul, Turkey's business and cultural hub, damaging windows but injuring no one. Police defused separate explosives in front of a cultural centre in the city.
The DHKP-C statement did not mention the Istanbul attacks.
Interior Minister Muammer Guler said earlier there was a "strong probability" that the DHKP-C, one of whose members blew himself up at an entrance of the U.S. embassy on February 1, killing a Turkish guard, was responsible.
"Various groups that we know to be against the (peace) process could have chosen these targets," Deputy Prime Minister Bulent Arinc told reporters. "I think this could have been done to frighten and intimidate the public."
The pro-Kurdish Peace and Democracy Party (BDP), which is involved in the peace process, condemned the Ankara attacks.
"Everybody in favour of a solution and peace must be more resolute, determined and strong in the face of such provocations and must never take a step back," a BDP statement said.
As well as Kurdish militants and far left groups, ultra-nationalists and Islamist radicals have also carried out attacks in Turkey in the past.
In the Istanbul attacks, an assailant threw a small bomb into the garden of a local state official's offices in the Maltepe district, broadcaster NTV said.
In Ankara, the AK Party attack shattered windows on the seventh floor of its headquarters, where Erdogan has an office, while two devices detonated outside the Justice Ministry several kilometres (miles) away.
A large Turkish flag was hung from the front of the AK Party building on Wednesday, concealing the missile damage. Erdogan had already gone on a visit to Denmark when the attacks occurred.
(Additional reporting by Jonathon Burch in Ankara; Writing by Daren Butler; Editing by Nick Tattersall and Mark Heinrich)