* Border guard killed, 6 hurt in clashes with armed Syrians
* Two rebel fighters killed in the clash -Syrian activist
* Turkish official describes armed group as smugglers (Updates with one killed, six wounded)
ANKARA, May 2 (Reuters) - One Turkish border guard was killed and six others were wounded on Thursday in a clash at the Syrian border with armed men, a security source said.
A Turkish official described them as smugglers and a Syrian opposition activist said some of them were Free Syrian Army (FSA) rebel fighters, two of whom were killed in the clash.
Media reports said 10 people, including civilians, were wounded in the clash.
Private broadcaster NTV said the Syrians had been waiting to cross at the border gate and opened fire when they were refused entry.
Reuters could not independently verify any of the reports.
FSA fighters, battling President Bashar al-Assad's forces in a civil war that has killed 70,000, regularly cross from Turkey, where they have been given sanctuary, into Syria to launch attacks on the army and then return.
Smugglers and rebels also take supplies into Syria from Turkey and bring back wounded fighters and refugees.
Photographs from Turkey's private Dogan news agency showed smoke rising from the border crossing and a fire engine at the scene. One showed a wounded man being loaded onto an ambulance. Broadcaster CNN Turk said cars at the crossing were set on fire.
Turkey is now sheltering more than 300,000 Syrians, most of them in camps along the 900-km (560-mile) frontier, and is struggling to keep up with the influx.
Ankara has denied reports that it has banned Syrians from crossing into Turkey, saying it operates an open-door policy but that at times it needs to regulate the flow of refugees.
Thursday's incident was a reminder of the strains on neighbouring countries as violence from the civil war in Syria, now into its third year, spills across borders.
In October, five Turkish civilians were killed in Akcakale when a mortar bomb fired from Syria landed on their house, prompting Turkey to fire back across the frontier. (Reporting by Jonathon Burch in Ankara, Seyhmus Cakan in Diyarbakir and Oliver Holmes in Beirut; Editing by Louise Ireland and Parisa Hafezi)
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