The explosives were found in a cemetery in the Esenyurt district by paramilitary troops, the Istanbul governor's office said in a statement.

The same type of explosives have, in the past, been used by both the outlawed Kurdistan Workers Party (PKK) and its splinter group, the Kurdistan Freedom Falcons (TAK).

Some 37,000 people have been killed since 1984 when the PKK, blacklisted by Turkey, the United States and the European Union, took up arms against the Ankara government for self-rule in southeastern Turkey.

The group has carried out bombings in both the southeast and major cities as part of its campaign.

Turkish officials say TAK is a cover the PKK uses to hit soft civilian targets, while the PKK denies any organic link with the group.