Russian President Vladimir Putin has expressed his optimism about the prospects of a solution to the years-long crisis in Syria, saying what is of utmost importance is the Arab country's territorial integrity, which is to be ensured.

The Russian leader made the remarks during a press conference on the sidelines of the 12th summit of the Group of Twenty (G20), the world's biggest economies, held in Germany's northern city of Hamburg on Saturday, the second and final day of the conference.

    It's laborious, but extremely important work to ensure Syria's territorial integrity, Putin said, adding, however, that with due respect to US Secretary of State Rex Tillerson, he is not a Syrian citizen to talk about the fate of Syrian President Bashar al-Assad.

    Mr. Tillerson is a much respected person. We love and respect him. But he's not a Syrian citizen, after all, and the future of Syria and the political future of President Assad should only be determined by the Syrian people, Putin said, in a reference to Tillerson's remark about Assad having no role in Syria.

The Russian president's comments came as the Kurdish fighters belonging to the US-backed Syrian Kurdish People's Protection Units (YPG) are currently engaged in a fierce battle against Takfiri Daesh terrorists in Raqqah, the terror group's de facto capital in the Arab country, in a bid to dislodge them from the embattled city, which was overrun by Takfiri elements in March 2013.

Turkey regards the YPG as the Syrian branch of the outlawed Kurdistan Workers' Party (PKK), which has been fighting an insurgency against the Turkish state for decades. Ankara deeply fears that the YPG will permanently hold parts of land in northern Syria after finishing with Daesh, putting the Turkish government at odds with Washington.

What has further infuriated Ankara about the US is Washington's move in arming the YPG fighters in their fighting against the Daesh. Although US Defense Secretary Jim Mattis promised Ankara that Washington would take back the weapons and equipment it had supplied to the YPG after curbing Daesh in Raqqah, Turkey says they will never return their weapons.

The YPG on Wednesday claimed that there would likely be a military confrontation between Kurdish fighters and Turkish troops as Ankara was preparing to launch a major offensive in northern Syria, calling it a declaration of war.

Elsewhere in his remarks, President Putin said that we see no Turkish preparations for hostilities in northern Syria, adding that Moscow was in contact with Kurds in the Arab country.

US President Donald Trump (R) and Russia's President Vladimir Putin shake hands during a meeting on the sidelines of the G20 Summit in Hamburg, Germany, on July 7, 2017. (Photo by AFP)

On Friday, Putin and his American counterpart Donald Trump reached an agreement to create de-escalation zones in southern Syria. The Russian president described the move as one of the breakthroughs during Friday's talks with Trump.

The de-escalations zones should become a prototype of such territories, which would be able to cooperate with each other and with the official government in Damascus, Putin said on Saturday. He also added that agreements on de-escalation zones in the Middle Eastern country must include outline of their boundaries and monitoring of their security.

The Russian president said Washington seemed to play a more pragmatic role in resolving the Syrian crisis, however, it doesn't seem to have changed drastically compared to the Obama administration, but there's an understanding that we can achieve a lot by joining forces.

Syria has been hit by deadly foreign-backed militancy since March 2011. Russia and the United States have been supporting opposing sides in the conflict in Syria with Moscow backing Syrian President Bashar al-Assad and Washington backing militants fighting to topple the Damascus government.