ANKARA/ISTANBUL (Reuters) - Turkey called for Syrian President Bashar al-Assad’s immediate ouster on Friday, voicing support for a U.S. missile strike on one of his air bases and saying the creation of safe zones to protect civilians was now more important than ever.

U.S. Navy guided-missile destroyer USS Ross (DDG 71) fires a tomahawk land attack missile in Mediterranean Sea which U.S. Defense Department said was a part of cruise missile strike against Syria on April 7, 2017. Robert S. Price/Courtesy U.S. Navy/Handout via REUTERS

Turkey, a NATO member and part of the U.S.-led coalition against Islamic State, has long argued there can be no peace in Syria under Assad. But following a rapprochement with Russia, it had appeared in recent months to accept the possibility of the Syrian leader staying on in a transitional role.

“It is necessary to oust this regime as soon as possible from the leadership of Syria,” Foreign Minister Mevlut Cavusoglu told reporters on Friday, in a hardening of Turkey’s tone.

“If he doesn’t want to go, if there is no transition government, and if he continues committing humanitarian crimes, the necessary steps to oust him should be taken.”

His comments came after the United States fired cruise missiles at a Syrian airbase from which, it said, a deadly chemical weapons attack was launched this week. It was the first direct U.S. assault on Assad’s government in six years of war.

President Tayyip Erdogan’s spokesman Ibrahim Kalin said the U.S. action marked “an important step to ensure that chemical and conventional attacks against the civilian population do not go unpunished” and said a no-fly zone should be enforced.

Erdogan himself has yet to comment on the U.S. missile strike but was quoted late on Thursday, before the U.S. action, as saying Turkey would welcome U.S. military action in Syria and would be ready to assist if needed.

The stance could complicate Turkish efforts to repair ties with Russia, damaged in November 2015 when Turkey shot down a Russian fighter jet near the Syrian border.

Relations have gradually been repaired since August, and Russia and Turkey jointly brokered a ceasefire in the Syrian city of Aleppo at the end of last year.

“There is a struggle for power between Russia and the United States over the future of Syria and Turkey is stumbling back and forth between the two,” said Metin Gurcan, a former military officer and security analyst at the Istanbul Policy Center.

“This is a period where Turkey shouldn’t make sharp U-turns ... sometimes we’re extremely pro-Washington and sometimes pro-Moscow. That could lead to Turkey being perceived as an inconsistent, unpredictable and therefore unreliable actor.”

Cavusoglu said the coalition had been informed of the U.S. missile strike and that he had spoken by phone with the French and German foreign ministers, although he did not say when.

He also said contacts had been initiated with Russian Foreign Minister Sergei Lavrov and U.S. Secretary of State Rex Tillerson.