MNA � Turkish President Recep Tayyip Erdogan said Tuesday that US sanctions on Iran are ineffective.

He made the remarks at the 11th Ambassadors' Conference in the capital Ankara.

Turkish president also reiterated that the US sanctions against Iran don't help restoration of regional peace and stability.

Elsewhere in his address, Erdogan said that Turkey�s counter-terrorism offensives will move forward to a �different phase� in northern Syria soon.

�We�ll move the process which we started with the Euphrates Shield and Olive Branch operations [in northern Syria] forward to a different phase very soon,� Anadolu quoted Erdogan as saying.

"If needed, Turkey will absolutely protect its national interests [in Syria] either via dialogue, soft power, coercive diplomacy instruments or realpolitik," he stressed.

Erdogan went on to say that country�s procurement of the Russian S-400 missile defense system was a �commercial� rather and �strategic� move, and criticized the US and EU for their biased reactions as they did not give the same response to the NATO members that previously bought S-300 system.

The attitude of Turkey's allies forced Turkish administration to buy Russian defense system, he added.

Although Turkey wanted to buy US Patriot missile system earlier, Washington did not respond positively when they were needed the most, according to Turkish officials, therefore Ankara initiated talks with Russia over purchase of Russian S-400 defense system.

Since 2017, Turkey and the US have been at odds over Turkey's decision to buy the S-400 and the U.S. threats to break its contract to sell Turkey F-35 fighter jets over the dispute.

The US claims the S-400 will be incompatible with NATO systems, an argument Turkey disputes.

NATO Secretary-General Jens Stoltenberg said that it is up to Turkey to make its own decisions on weapons systems purchases.