The Syrian leader's comments came after it was revealed a truce has been agreed for a "nationwide cessation" of violence
Syrian President Bashar al Assad has vowed to retake the entire country but warned it could take a "long time", as international pressure grows for a ceasefire.
Speaking in the capital Damascus on Thursday, Mr Assad said he supported peace talks, but that negotiations do "not mean that we stop fighting terrorism".
The Syrian leader's comments came after it was revealed a truce has been agreed for a "nationwide cessation" of violence in a week's time.
However, Islamic State, al Nusra and other terrorist groups will not be involved - and Russia has said it will continue its bombing campaign.
In a wide-ranging interview with the AFP news agency, Mr Assad:
Syria's civil war has been raging since 2011, but the conflict entered a new phase last year when Russia started providing air support to government forces.
Aided by Russian air power, regime troops have nearly encircled Aleppo, Syria's second city.
Mr Assad said his eventual goal was to take back all of Syria, large parts of which are under control of rebel forces or IS.
"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," Mr Assad added.
He 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".
Mr Assad's interview is the first he has given since the effective collapse of peace talks in Geneva earlier this month.
The talks have been "paused" until 25 February, and the truce is intended to bolster efforts for new negotiations.