AMMAN (Reuters) - Kurdish militants sought to consolidate their control of an oil-producing region in northeastern Syria on Sunday after seizing a border crossing with Iraq from Islamist rebels, activists said.
Fighters linked to the Kurdistan Workers Party (PKK), which has fought in neighbouring Turkey for decades, were clearing pockets of resistance of the al Qaeda-linked Islamic State of Iraq and the Levant, al-Nusra Front, and Ahrar al-Sham in the border town of Yarubiya, Syrian opposition sources said.
"The Kurds are now in control of the Yarubiya border post. They now have a clear route to market the region's oil, which should belong to all Syrians. Thousands of Arabs have fled," said Yasser Farhan, a member of the opposition Syrian National Coalition.
The northeastern province of Hasakah, which borders Iraq and Turkey, has a population of over one million, 70 percent Kurdish and 30 percent Arab. The fighting there deepens sectarian and ethnic faultlines in Syria and threatens to draw neighbouring powers into the country's civil war.
A statement by the Syrian National Coalition said Iraqi ground forces had attacked Yarubiya on Saturday in coordination with the Kurdish militia. Syrian rebel sources said Syrian warplanes had also bombarded the town.
"The Iraqi government has committed a grave error by its unprecedented interference in Syrian affairs," the statement said, adding that the Shi'ite-dominated Baghdad government had been aiding the transfer to Syria of Iraqi Shi'ite militia who are fighting alongside President Bashar al-Assad's forces.
An Iraqi security official denied involvement in the capture of Yarubiya. "The last thing we need is to get dragged into military combat in Syria. We will not engage in any way," he said.
Other Iraqi officials said some wounded Kurdish fighters had been evacuated in Iraqi army Humvees and taken to areas controlled by Iraqi Kurdish fighters, then into Iraq.
Rami Abdelrahman, head of the pro-opposition Syrian Observatory for Human Rights monitoring group, said Kurdish fighters had taken over 90 percent of Yarubiya town.
Video footage released by the group showed Kurdish fighters manning a tower at the crossing and others carrying the flag of the Kurdistan People's Protection Units militia.
In a statement, the militia said three of its members had been killed in four days of fighting to take Yarubiya, which it said Islamist militants had used as a base to prepare bombs and send suicide bombers into Kurdish regions. There was no immediate casualty figure for their opponents.
Kurds in Syria have played a complex role in Syria's civil war, which has pitted mostly Sunni Muslim rebels against Assad's Alawite minority, an offshoot of Shi'ite Islam.
Different Kurdish militia have fought on both sides while the rise of al Qaeda has strengthened Kurdish militants linked to the PKK, which has been traditionally opposed by non-violent Kurdish political parties.
Kurds comprise around 10 percent of Syria's 23 million population. They are concentrated in Hasakah, in parts of Damascus and in Ifrin province north of Aleppo, where there has also been intense fighting between Kurds and Arab rebel units.
Since the uprising, Assad has pulled many of his forces from the mostly Kurdish northeast but kept a presence for his intelligence and secret police units in Qamishli and Hasakah, the two major cities in the area, activists said.
Massoud Akko, a prominent Kurdish dissident living in exile in Norway, said it was normal for the Kurds to try to secure as much territory as they could in their home region.
"Syria is already becoming divided. The Islamists and the Free Syrian Army have much of the north and east, while Assad and his loyalists are holding out in the centre and the coast," he said.
Akko said that while the Kurdish community had misgivings about the PKK and its allies, they were regarded as a bulwark against al Qaeda.
"With the Syrian National Coalition remaining silent on al Qaeda and economic conditions deteriorating in the northeast, the Kurds have no one to turn to except the PKK and its allies, and the Iraqi Kurdistan government," he said.
Additional reporting by Oliver Holmes in Beirut, Isabel Coles in Arbil and Ziad al-Sinjary in Mosul; Editing by Alistair Lyon