ANKARA - Turkish president and other senior officials said on Wednesday that the Operation Peace Spring, launched earlier in the day, aims to eliminate terrorism along its border and establish a safe zone to facilitate return of Syrian refugees.

"The Turkish Armed Forces, together with the Syrian National Army, just launched Operation Peace Spring against the PKK (Kurdistan Workers' Party), YPG (People's Protection Units) and Daesh (Islamic State) militants in northern Syria," Turkish President Recep Tayyip Erdogan tweeted.

"Our mission is to prevent the creation of a terror corridor across our southern border, and to bring peace to the area," he said.

"Operation Peace Spring will neutralize terror threats against Turkey and lead to the establishment of a safe zone, facilitating the return of Syrian refugees to their homes. We will preserve Syria's territorial integrity and liberate local communities from terrorists," Erdogan added.

Turkish army shelled Ras al-Ain and Tal Abyad line in northern Syria with storm howitzers, backed by strikes by F16 fighter jets, a Turkish official told Xinhua on condition of anonymity.

The YPG, which controls the east of the Euphrates, was a key partner of the United States in the fight against the IS, but Ankara considers it as a "terrorist" offshoot of the outlawed PKK in Syria.

Semi-official Anadolu Agency reported shortly after Turkey launched the offensive that two mortar shells hit the southern Turkish border town of Ceylanpinar, across Syrian town Ras al-Ain, with no casualties reported.

The United States, Russia, Britain, Germany, France and Italy as well as NATO and the United Nations secretary-general were informed of the operation as of 2:00 pm local time (1100 GMT) and the operation started at 4:00 pm, the Turkish Defense Ministry said.

The operation is in line with the country's right of self-defense and international law as well as UN Security Council resolutions regarding fight against terror, while respecting Syria's territorial integrity, Turkish Defense Ministry said in a written statement.

"As in the Operation Euphrates Shield and the Operation Olive Branch ... only the terrorists and their shelters, positions, weapons, tools, and equipment are targeted and care and attention are paid to avoid damage to the historical, cultural, religious structures, infrastructure facilities and potential elements of friendly and allied countries in the region," the statement added.

Turkey also issued a diplomatic note to the Syrian Consulate in Istanbul on Operation Peace Spring, Turkish Foreign Minister Mevlut Cavusoglu told reporters.

NATO Secretary-General Jens Stoltenberg has called for avoiding actions that may further destabilize the region, escalate tensions and cause more human suffering.

Syrian Foreign Ministry on Wednesday condemned the Turkish military offensive on Kurdish positions in northern and northeastern Syria, stressing the Syrian government's determination to confront the "Turkish aggression by all means."

Last Sunday, the White House said that it will not support or be involved in the Turkish operation in northern Syria and will withdraw its troops from "the immediate area." The move was widely considered as "a green light" to a Turkish incursion into Syria.

In 2016, Turkey launched the Operation Euphrates Shield and in 2018 the Operation Olive Branch in northwestern Syria against the YPG.

Ankara says that it plans to resettle 2 million Syrian refugees in Turkish territory to a 30-km deep safe zone to be set up in northern Syria, stretching from the Euphrates River to the Iraqi border, including Manbij town.