* Five-month old baby and two toddlers among dead
* Militants launch simultaneous attack on security complex
* Region hit by daily violence since insurgency reignited (Adds scene in Cizre, investigation of academics)
By Seyhmus Cakan
CINAR, Turkey, Jan 14 (Reuters) - Kurdish militants have attacked a police station in southeast Turkey with a truck bomb, killing six people including a baby and two toddlers, in one of the biggest strikes since the conflict reignited in July, security officials said on Thursday.
The overnight blast ripped the facade off the station in the small town of Cinar. A Reuters reporter saw nearby windows blown out, shop shutters mangled and streets covered in debris.
The mainly Kurdish region has suffered a surge in violence since a two-year ceasefire between the state and Kurdistan Workers' Party (PKK) rebels collapsed, reviving an insurgency that has killed 40,000 people over three decades.
The conflict is a challenge to Turkey's security forces, which are fighting on two fronts. On Tuesday, 10 German tourists were killed in Istanbul in a suicide attack by a suspected Islamic State militant.
Prime Minister Ahmet Davutoglu said a five-month-old baby was among the dead in Cinar, vowing in a speech that Turkey would pursue its fight against "every kind of terror".
Security sources said a one-year-old and a five-year-old had also died, along with a police officer and an unnamed fifth person, and that 39 people were wounded, including six police.
SEARCH FOR BODIES
PKK militants attacked the police station and adjoining accommodation at around 11:30 p.m. (2130 GMT), the provincial governor's office said in a statement.
There was no immediate claim of responsibility. As rescue workers searched for bodies, the Reuters reporter saw a sixth body being pulled from the wreckage. A security source said it was that of a policeman's wife.
"It was a really loud blast, as if it was in our house," said Ali Devran, a resident in his 30s. "We went and helped carry the wounded to ambulances. Some had suffered burns."
A security source said 1.5 tonnes of explosives were used in the blast.
Coinciding with the bomb attack, PKK fighters opened fire on a nearby security complex, triggering a firefight, but no casualties were reported, the statement said.
The PKK, designated a terrorist group by Turkey, the United States and the European Union, says it is fighting for autonomy and greater rights for Turkey's Kurds.
Since it launched its insurgency in 1984, fighting has stayed largely in the countryside, but the latest violence has focused on urban areas, where the PKK youth wing has set up barricades and dug trenches to keep out security forces.
Two towns near the Syrian and Iraqi borders, Silopi and Cizre, along with the Sur district of the regional capital Diyarbakir, have been subjected to round-the-clock curfew for more than a month amid operations by security forces.
Civilians have been caught in the middle. Figures from the pro-Kurdish HDP party show 87 civilians have been killed in Sur and the two towns in that time.
Reuters TV footage showed a tank driving along the streets of Cizre on Thursday, where homes and buildings were damaged by shelling.
Following a heavy blast, the footage showed dozens of people carrying a wounded child with blood on her head, wrapped in a blanket, to a minivan, a white flag attached to its antenna in an apparent effort to get through the curfew.
In his speech, Davutoglu slammed a declaration signed by more than 1,100 academics criticising security operations and calling for an end to curfews and fresh peace efforts.
"It is saddening that our academics have signed such a declaration when we are talking about the fight against terror, ISIS (Islamic State) on one side and a separatist terror group that killed a baby on the other," he said.
Prosecutors and universities have launched investigations into several of the academics who signed the statement on suspicion of terrorist propaganda and inciting hatred. The more than 1,000 signatories included U.S. philosopher Noam Chomsky. (Additional reporting by Melih Aslan in Istanbul, Ercan Gurses in Ankara; Writing by Daren Butler; Editing by Nick Tattersall, Kevin Liffey and Peter Millership)