ANKARA (Reuters) - A Turkish soldier and a guard were killed by a roadside bomb in the southeastern city of Van, military sources said on Friday, adding that an aerial operation was underway against the suspected Kurdish militant attackers.

An explosion hit Turkish security forces carrying out reconnaissance along a road in Van, the sources said. Initial reports pointed to an explosive device planted by members of the outlawed Kurdistan Workers’ Party (PKK), they said.

The second victim of the blast was a village guard, part of a paramilitary force employed by the state to support security forces in southeast Turkey.

The region has been ravaged by violence since a ceasefire between the PKK and the state fell apart last July. More than 40,000 people, many of them Kurds, have died since the autonomy-seeking PKK, designated a terrorist organization by Turkey, the United States and the European Union, first took up arms against the government in 1984.

Turkey has tightened security ahead of a historic referendum on Sunday, but the PKK on Wednesday claimed responsibility for a bomb attack on a police compound in the southeastern city of Diyarbakir that killed three people.