President Bashar al-Assad vows to retake whole of Syria but warns could 'take long time'

Syrian President Bashar al-Assad has vowed to regain control of the entire country but warned it could "take a long time" as international pressure grows for a ceasefire.

Speaking at his office in Damascus on Thursday, Assad said he supported peace talks but that negotiations "do not mean that we stop fighting terrorism."

He said his regime's eventual goal was to retake all of Syria, large swathes of which are under the control of rebel forces or the Islamic State jihadist group.

"Regardless of whether we can do that or not, this is a goal we are seeking to achieve without any hesitation," he said.

"It makes no sense for us to say that we will give up any part," he added.Assad said it would be possible to "put an end to this problem in less than a year" if opposition supply routes from Turkey, Jordan and Iraq were cut.

But, if not, he said, "the solution will take a long time and will incur a heavy price."

The interview, with Agence France Presse, was the first he has given since the effective collapse of a new round of peace talks in Geneva.

• Read more: World powers agree Syria ceasefire plan but Russian bombing continues

Assad said a major Russian-backed government offensive under way in the northern province of Aleppo was aimed mainly at severing the opposition's supply route from Turkey.

He said he saw a risk that Turkey and Saudi Arabia, key backers of the opposition, would intervene militarily in Syria.

During the interview, Assad rejected UN allegations of regime war crimes, describing them as "politicised" and lacking evidence.

Addressing the massive flow of refugees from his country, he said it was up to Europe to stop "giving cover to terrorists" so that Syrians could return home.

"I would like to ask every person who left Syria to come back. They would ask 'why should I come back? Has terrorism stopped?'", he said.

Instead, he urged Europe's governments "which have been a direct cause for the emigration of these people, by giving cover to terrorists in the beginning and through sanctions imposed on Syria, to help in making the Syrians return to their country."