Syrian rebel forces occupied a second border post with Turkey on Sunday, three days after taking control of the frontier crossing of Bab Al-Hawa, a Turkish diplomat told AFP.
Amateur video distributed by the Syrian Observatory for Human Rights watchdog group showed armed men carrying the flag of the Syrian uprising at the Al-Salama border crossing.
The diplomat, speaking on condition of anonymity, said rebel forces took control of the Al-Salama outpost north of the Syrian city of Aleppo at 0400 GMT.
The crossing faces the southern Turkish border post of Oncupinar in the southern Kilis province.
The video footage shows one fighter, who identifies himself as spokesman for the "Northern Storm Brigade" of the rebel Free Syrian Army, said the border post was now under their control.
"Bab Al-Salama has been liberated from the hands of Assad's mafia, after a suffocating siege on them," he said, without giving his name.
Regime forces "withdrew after suffering losses," he added, describing Turkey as a "sister nation."
Several men standing behind him hold up their weapons to celebrate, chanting: "Allahu Akbar! (God is greatest)."
The man called the takeover of the outpost a step on the road "to liberate Aleppo, and then Damascus, and then the presidential palace."
Rebel forces gained control of the Bab al-Hawa crossing between Syria and Turkey on Thursday.
But by Saturday evening, a group of some 150 foreign fighters calling themselves as Islamists were in control of the Bab al-Hawa post, an AFP photographer said.
Some of the fighters said they belonged to Al-Qaeda in the Islamic Maghreb (AQIM), while others claimed allegiance to a group called Shura Taliban.
They were armed with Kalashnikov assault rifles, rocket launchers and improvised mines.
The fighters identified themselves as coming from a number of countries: Algeria, France, Egypt, Saudi Arabia, Tunisia, the United Arab Emirates and the Russian republic of Chechnya.
There are seven functioning border posts along the nearly 900-kilometre (560-mile) frontier.