By Laila Bassam and Tom Perry

DAMASCUS (Reuters) - The Syrian government expects a tough battle for Aleppo, the city that has become the focal point of the country's long civil war, but is confident of victory and says it won't be a long fight.

Damascus aims to seal the border with Turkey, a major sponsor of the insurgents fighting President Bashar al-Assad, and to retake rebel-held areas of what was Syria's biggest city and industrial hub before the conflict began in 2011.

"These battles are not easy, but the day will come, God willing, when all Aleppo - its rural areas and the occupied part of the city - will return to state authority," Syrian Information Minister Omran al-Zoubi said in an interview on Wednesday.

He declined to predict how long the campaign would last, but added: "I do not expect the battle of Aleppo to go on long."

The Syrian government has made significant gains against rebels north of the city in the last week, in a dramatic advance backed by Russian air strikes and allies on the ground including Lebanon's Hezbollah and Iranian fighters.

The government assault helped to derail already struggling Geneva peace talks this month. Russia's intervention has tipped the war Assad's way, reversing gains rebels made last year.

PRIZE

Aleppo would be the biggest strategic prize in years for Assad's government in a conflict that has killed at least 250,000 people and driven 11 million from their homes.

The offensive has already cut vital rebel supply lines into opposition-held areas of the city from Turkey. Tens of thousands of people have fled toward the border.

Zoubi said the insurgents were well-financed and armed, naming groups that have received U.S.-made TOW anti-armor missiles, as well as the al Qaeda-linked Nusra Front, and other jihadists such as the Turkistan Islamic Party.

"They have TOW, they have tanks, they have armored cars, they have bombs, they have many weapons," Zoubi said.

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Since Russia began its air campaign on Sept. 30, the Syrian army and its allies have launched major ground offensives in the northwestern province of Latakia bordering Turkey and in Deraa province neighboring Jordan.

While rebel forces are under pressure in both Latakia and Aleppo, government forces have yet to launch a major attack against them in Idlib province, which also borders Turkey and is a stronghold of groups including the Nusra Front.

Zoubi indicated Idlib might not be attacked imminently. "Idlib is within the goals of ... the overall military operation, but when its time comes, it will have its own plan," he said.

FOOD SUPPLIES

The United Nations said on Tuesday supplies of food to hundreds of thousands of civilians could be cut off if government forces encircle rebel-held parts of Aleppo.

Zoubi said one goal was to open the main highway south to Damascus and "break the siege" imposed by insurgents.

Since the state lost control of the highway, supplies to government-held parts of Aleppo have been sent via a longer road that passes close to areas held by Islamic State to the east where it is being bombed by a U.S.-led alliance.

Damascus describes all the groups fighting it as terrorists controlled by regional enemies including Saudi Arabia and Turkey.

Saudi Arabia, one of the states that wants to see Assad gone from power, said last week it would be ready to send troops to Syria as part of any ground operation by the U.S.-led alliance.

"Even thinking about this is a big adventure and gamble, the results of which I don't believe Saudi can bear, neither for its army or its internal situation," Zoubi said.

He also said increasing military pressure on insurgents could lead to more attacks like the suicide car bombing in Damascus on Tuesday - the first of its type in the capital in two years. The attack, which killed at least three people, was claimed by Islamic State.

(Editing by Andrew Roche)