ANKARA, Turkey -- Turkish warplanes struck suspected Kurdish rebel positions in Iraq and Syria on Tuesday, drawing condemnation from Baghdad and criticism from the U.S.-led coalition fighting the Islamic State group, which is allied with Kurdish factions in both countries.

The Syrian Kurdish militia known as the People's Protection Units, or YPG, said 20 of its fighters were killed and 18 wounded. The YPG is a close U.S. ally against IS but is seen by Ankara as a terrorist group because of its ties to Turkey's Kurdish rebels.

The airstrikes also killed five members of the Iraqi Kurdish militia known as the peshmerga, which is also battling the extremist group with help from the U.S.-led coalition.

YPG spokesman Redur Khalil said the Turkish aircraft struck the group's headquarters in Karachok, in Syria's northeastern Hassakeh province, causing extensive damage to the headquarters as well as nearby civilian property.

The YPG is among the most effective ground forces battling IS, but Turkey says it is an extension of the outlawed Kurdistan Workers' Party, or PKK, and that PKK fighters are finding sanctuaries in neighbouring Iraq and Syria.

A Turkish military statement said the pre-dawn strikes hit targets on Sinjar Mountain in northern Iraq and a mountainous region in Syria. It said the operations were conducted to prevent infiltration of Kurdish rebels, weapons, ammunition and explosives from those areas into Turkey.

The military said in a later statement that the air strikes hit shelters, ammunition depots and key control centres, adding that some 40 militants in Sinjar and some 30 others in northern Syria were "neutralized."

In an emailed statement to The Associated Press, the U.S.-led coalition said Iraq's neighbours need to respect Iraqi sovereignty.

"We encourage all forces to ... concentrate their efforts on ISIS and not toward objectives that may cause the Coalition to divert energy and resources away from the defeat of ISIS in Iraq and Syria," it said, using another acronym for IS.

Iraq's Foreign Ministry denounced the strikes as a "violation" of its sovereignty and called on the international community to put an end to such "interference" by Turkey.

"Any operation that is carried out by the Turkish government without any co-ordination with the Iraqi government is totally rejected," Foreign Ministry spokesman Ahmad Jamal told The Associated Press.

He cautioned against a broader Turkish military operation, saying it would "complicate the issue and destabilize northern Iraq."

Although Turkey regularly carries out airstrikes against PKK targets in northern Iraq, this was the first time it has struck the Sinjar region. Turkey has long claimed that the area was becoming a hotbed for PKK rebels.

Sinjar Mayor Mahma Khalil said the strikes started at around 2:30 a.m., killing five members of the peshmerga and wounding nine. Khalil said he was not aware of any casualties among PKK rebels.

The peshmerga command called on the PKK to withdraw from the Sinjar region, saying the "PKK must stop destabilizing and escalating tensions in the area."

The PKK has led an insurgency in southeast Turkey since 1984, and is considered a terror organization by Turkey and its allies.

Last year, Turkey sent troops into Syria to back Syrian opposition fighters in the battle against IS and curb the expansion of the U.S.-backed Syrian Kurdish forces.

The Syrian Kurdish forces denounced Tuesday's strikes on their positions as "treacherous," accusing Turkey of undermining the anti-terrorism fight. The Syrian Kurds have driven IS from large parts of Syria and are currently closing in on Raqqa, the de facto capital of the extremists' self-styled caliphate.

"By this attack, Turkey is trying to undermine Raqqa operation, give (IS) time to reorganize and put in danger lives of thousands of" displaced, the YPG said on its Twitter account.

In Damascus, meanwhile, officials denounced new U.S. sanctions imposed by the Trump administration on 271 people linked to the Syrian agency said to be responsible for producing non-conventional weapons. The move was part of an ongoing U.S. crackdown in response to Syrian President Bashar Assad's alleged use of chemical weapons.

Khaled Abboud, a member of parliament, said the centre is "purely a research centre, mostly for agricultural studies."

"The sanctions are new attempts by the U.S. administration to put pressure on the Syrian state," he told The Associated Press, adding that the centre is a "peaceful research centre."

The U.S. has blamed Assad for a chemical weapons attack earlier this month that killed more than 80 civilians in the rebel-held northern Idlib province. Syrian officials strongly deny the charges.

An airstrike in Idlib on Tuesday killed at least 12 people, including civilians, the Britain-based Syrian Observatory for Human Rights said. The area is controlled by hard-line rebel factions, some associated with al-Qaida. The Observatory, which relies on contacts inside Syria, said it suspected a Russian jet was behind the strike.

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Associated Press writers Sarah El Deeb and Philip Issa in Beirut, Qassim Abdul-Zahra in Baghdad and Albert Aji in Damascus, Syria, contributed to this report.