(Recasts with army statement saying clash was with Kurdish militants, not smugglers, raises death toll)
DIYARBAKIR, Turkey, July 22 (Reuters) - At least eight people were killed in clashes between the Turkish military and Kurdish rebels on the country's Syrian border, the army said on Tuesday, apparently the most serious outbreak of violence since the militants declared a ceasefire last year.
A local official earlier pointed the finger at smugglers, after an armed group crossing the border from Syria into Turkey ignored calls to stop and opened fire on an army outpost.
Three border guards were wounded, two of whom later died, after they came under attack from around 15 people trying to cross into Turkey, the Turkish General Staff said in a statement.
Reinforcements were deployed and at least six "terrorists" from the outlawed Kurdistan Workers Party (PKK) or its affiliate, the Syria-based Democratic Union Party (PYD), were believed to have died in the clash, the army said.
There was no immediate word from either the PKK or PYD.
The clash could be a blow to efforts led by Prime Minister Tayyip Erdogan to bring an end to the PKK's insurgency, which has left more than 40,000 people dead over three decades.
Earlier this month Turkish deputies passed a bill giving legal recognition to negotiations for the first time, a move hailed as an important step on the path to peace.
Erdogan is hoping to become Turkey's first directly elected president in polls due on August 10, and may need to rely on votes from parts of the Kurdish community to help him win.
The ceasefire - negotiated with the PKK's imprisoned leader Abdullah Ocalan - has largely held since it came into force last March.
Tensions in south-eastern Turkey have risen in recent months however, after violent clashes between security forces and Kurds protesting against the building of military outposts in Kurdish areas. (Reporting by Seyhmus Cakan in Diyarbakair and Daren Butler in Istanbul. Writing by Jonny Hogg, editing by John Stonestreet)