Saudi Arabia has deployed 30,000 soldiers to its border with Iraq after Iraqi soldiers withdrew from the area, the Saudi-owned Al Arabiya television reported on Thursday.
The kingdom shares an 800km border with Iraq, where Islamic State insurgents and other Sunni militant groups seized towns and cities in a lightning advance last month.
King Abdullah has ordered all necessary measures to protect the kingdom against potential “terrorist threats”, state news agency SPA reported.
The Dubai-based Al Arabiya reported that Saudi troops had fanned into the border region after Iraqi government forces abandoned their positions, leaving the Saudi and Syrian frontiers unprotected.
The satellite channel said it had obtained a video showing some 2,500 Iraqi soldiers in the desert area east of the Iraqi city of Karbala after pulling back from the border.
An officer in the video aired by Al Arabiya said the soldiers had been ordered to quit their posts without justification.
The Saudi troop movement was also confirmed by a US defence official, who said the kingdom’s forces were massing along its border with Iraq in response to Islamic State’s advance toward the frontier.
However, the Iraqi prime minister Nouri Al Maliki’s Military spokesman, Qassim Atta, later denied that Iraqi troops had withdrawn from the border with Saudi Arabia.
Militants from the Al Qaeda breakaway Islamic State control large areas of western north-west Iraq after launching an offensive with allied Sunni fighters on June 9.
The group has also captured large areas across the border in Syria, where it is fighting both troops loyal to Bashar Al Assad and other rebel groups seeking to depose the Syrian president.
On Thursday, the group seized several towns and villages in Deir Ezzor province bordering Iraq as well as Syria’s largest oil field as rival factions gave up the fight, activists said.
The new gains effectively expand and consolidate areas held by the group in territory straddling the border between the two conflict-ridden countries.
On Sunday, the group declared a “caliphate” straddling Syria and Iraq, referring to an Islamic system of rule that was abolished nearly 100 years ago, in a move that has angered other rebel groups and Islamists, who declared it a ‘heresy”.
With the seizure the Al Omar oil field in Deir Ezzor, the Islamic State now controls most oil and gas fields in the oil-rich province, most of whose countryside is also under its control.
The capture “comes after [Al Qaeda affiliate] Al Nusra Front withdrew from the oil field without a fight”, said the Britain-based Syrian Observatory for Human Rights, which monitors the conflict in Syria.
The Islamic State’s campaign in Iraq is threatening to divide the country along sectarian and ethnic lines, with the leader of the Kurdish autonomous region announcing plans on Thursday to hold a referendum on independence from Baghdad’s rule.
The rugged, mountainous region north of the country has about 4.69 million people and has long been at odds with the federal government in Baghdad.
The independence issue has been brought to the fore since Kurdish forces took control of the disputed oil-rich city of Kirkuk after federal government troops withdrew in the face of the Islamic State offensive.
Massoud Barzani, the president of the Kurdistan Regional Government, told the region’s legislature in a speech Thursday to set up an electoral commission to “hurry up” and prepare for “a referendum on self-determination”.
“It will strengthen our position and will be a powerful weapon in our hands,” Mr Barzani said.
The prospect of an independent state is made more attractive by what the Kurds say is Baghdad’s unwillingness to resolve the issue of disputed territory and its late and insufficient budget payments to the region this year.
Mr Barzani has said that Kurdish forces will not withdraw from territory they occupied after federal security forces withdrew.
Mr Al Maliki rejected this, saying “no one has the right to exploit the events that took place to impose a fait accompli” and that the Kurds’ steps towards self-determination had no constitutional grounding.
On the ground, Iraqi forces were struggling to make a breakthrough in an operation to retake the city of Tilkrit from militants that was launched last week.
A police lieutenant colonel said security forces clashed with militants near the city on Thursday.
The governor of Salaheddin province, Ahmed Abdullah Juburi, had said on Wednesday that security forces were “advancing slowly because all of the houses and burned vehicles [en route to Tikrit] have been rigged with explosives, and militants have deployed lots of roadside bombs and car bombs”.
It would be days before security forces could make a concerted push into the city, the capital of Salaheddin province, he said.
* Reuters with additional reporting from Associated Press and Agence France-Presse