The killing of Saudi journalist Jamal Khashoggi is an issue larger than one which concerns only Turkey and Saudi Arabia, presidential spokesman Ibrahim Kalin said on Monday.

"The issue is not between Turkey and Saudi Arabia. Turkey is taking necessary steps to unveil the incident under international and national law," Kalin said at a news conference in capital Ankara.

"The issue is to shed light on an atrocious murder," he added.

Kalin said Turkey has been carrying out "sensitive and comprehensive" investigation on the case of Khashoggi, who had gone missing since entering the Saudi Consulate in Istanbul on Oct. 2.

After days of denying to know his whereabouts, Saudi Arabia on Saturday claimed Khashoggi died during a fight inside the consulate.

On the day of Khashoggi’s disappearance, 15 other Saudis, including several officials, arrived in Istanbul on two planes and visited the consulate while he was still inside, according to Turkish police sources. All of the identified individuals have since left Turkey.

A joint Turkish-Saudi team completed an investigation into the case on Thursday after searching the residence of the consul general as well as the Saudi Consulate in Istanbul.

"The stance of our president [Recep Tayyip Erdogan] is very clear since the beginning. Nothing will remain hidden regarding this incident," Kalin added.

US thanks Turkey for Syria deal 

Kalin reminded reporters that Erdogan and U.S. President Donald Trump discussed the Khashoggi case, fight against terrorism and latest developments in Syria in Sunday's phone call.

"Trump thanked our president over the Idlib deal and said: 'You prevented a major humanitarian disaster via this deal in Idlib, where 3.5 million people live'," Kalin said.

In September, Erdogan and his Russian counterpart Vladimir Putin agreed to establish a demilitarized zone in Syria's northwestern province of Idlib.

About the latest developments on the Turkey-U.S. joint patrol in Syria's Manbij, Kalin said: "U.S. officials have started taking necessary steps to accelerate the process. 

"The ongoing joint training in [Turkey's southeastern province] Gaziantep will be completed in the upcoming days and joint patrols around Manbij will start soon."

The Manbij deal between Turkey and the U.S. focuses on the withdrawal of terrorist YPG/PKK forces from the city in Aleppo province, northern Syria to stabilize the region.

In its more than 30-year terror campaign against Turkey, the PKK has taken 40,000 lives, including many women and children. The YPG is its Syrian branch.

Kalin also said Turkey expects the U.S. to remove sanctions "as soon as possible" so as to contribute to normalization of bilateral ties.

He added some issues remain a problem between Ankara and Washington, particularly the fight against the Fetullah Terrorist Organization (FETO).

He said Turkey expects the U.S. to take concrete steps regarding FETO, PYD and PKK.

FETO and its U.S.-based leader Fetullah Gulen orchestrated the defeated coup attempt in Turkey on July 25, 2016, which left 251 people martyred and nearly 2,200 injured.

Eastern Mediterranean

Kalin said Turkish seismic vessels working in the Eastern Mediterranean will continue activities in the region. 

On Thursday, a Greek frigate trying to interfere with Barbaros Hayreddin Pasa, a Turkish seismic vessel, was blocked by the Turkish navy.

The incident prompted an immediate response from Turkish officials, who warned Greece against taking actions in the Mediterranean Sea that would spark tensions in the region.

"Turkey will never give up on its rights in the Eastern Mediterranean safeguarded by international law," Kalin said.

On Thursday, Turkey's Foreign Ministry said in a statement that Ankara will continue to exercise its sovereign rights and jurisdiction stemming from international law over its continental shelf and called on Greece to abstain from acts that would cause an escalation in the region.