Turkish soldiers stand guard as a Syrian boy waits behind a border fence to cross into Turkey. (Osman Orsal/Reuters)

The United Nations and Human Rights Watch accused Turkish security forces Tuesday of committing serious human rights violations against Turkish civilians and Syrian refugees in recent months.

The allegations come as Europe has pushed Turkey to help stem the flow of migrants to Europe while also calling on Turkish authorities to soften anti-terrorism laws to limit rights abuses.

Turkish security forces may have deliberately shot civilians, destroyed infrastructure, carried out arbitrary arrests and triggered a wave of displacement in an ongoing military campaign against ethnic Kurdish separatists in the country’s southeast, U.N. human rights chief Zeid Ra’ad al-Hussein said Tuesday. He urged Turkish authorities to allow independent investigators to probe the alleged attacks, which he called “extremely alarming.”

A separate report by the New York-based Human Rights Watch accused Turkish border guards of shooting at and beating Syrian asylum seekers along Turkey’s frontier with the war-ravaged nation. At least five people have been killed in the past two months, the rights group said. Turkish officials have previously denied reports that border guards have fired at refugees or forced them back into Syria.

A senior Turkish official said Tuesday that the government is “unable to verify” the authenticity of a video, posted by Human Rights Watch, that purports to show the bodies of Syrian refugees killed by Turkish forces at the border.

Turkey’s state-run news agency said at least three people were killed and 20 hurt in a car bombing May 10, 2016, that targeted a bus carrying police officers in Diyarbakir. Here, security and forensics officers work at the site of the explosion. (Mahmut Bozarslan/AP)

Turkey “maintains an open-door policy” toward refugees, said the official, who spoke on the condition of anonymity because of the sensitivity of the issue. But “the open-door policy isn’t the same as open borders,” the official said. “Turkey admits refugees at designated points of entry.”

Human Rights Watch on Tuesday called on Turkey to investigate the claims in its report, including that border guards had fired on Syrians fleeing artillery fire.

The reports are likely to bring further scrutiny to a controversial deal made by European and Turkish leaders to halt the flow of migrants to Europe. Turkey has agreed to accept the return of asylum seekers whose applications are rejected by the European Union in exchange for more than $6 billion in aid and visa-free travel for Turkish citizens. But Turkey’s recent slide toward authoritarianism has alarmed critics, and the European Commission, the E.U.’s executive body, called on Turkey earlier this month to modify its terrorism legislation.

The anti-terrorism laws have been used to target journalists and academics — and to pursue the government’s war against Kurdish militants in southeastern Turkey.

The decades-old conflict between Turkey’s government and the armed Kurdistan Workers’ Party (PKK) flared last year after peace talks broke down. Since then, PKK guerrillas have killed scores of members of the Turkish security forces, and other Kurdish militants are suspected in bomb attacks in the capital, Ankara.

A car bomb targeting a police convoy in the southeastern city of Diyarbakir killed three people Tuesday, Turkey’s state-run news agency reported.

Also Tuesday, the United Nations said many majority-Kurdish towns and villages in the southeast had been “sealed off for weeks” by Turkish security forces “and are still next to impossible to access.”

Hussein, the U.N. high commissioner for human rights, said mortar and other artillery fire in these areas have caused “highly disproportionate destruction of property.” He also said he has received reports that “ambulances and medical staff were prevented from reaching the wounded.”

Most disturbing of all, Hussein said, are reports suggesting more than 100 people were burned to death as they sheltered in basements that had been surrounded by security forces in the southeastern town of Cizre.

The allegations “are extremely serious and should be thoroughly investigated,” Hussein said. The Turkish government has not responded positively to U.N. requests to visit the area, he said.

In response to Hussein’s allegations, the Turkish official said the U.N. statement “does not accurately reflect the situation in southeastern Turkey.”

“Last year, the PKK, which both Turkey and the U.S. consider a terrorist organization, started engaging the security forces in residential areas as opposed to the countryside, where they traditionally operated,” the official said. “Throughout the counterterrorism campaign, the Turkish security forces went to great lengths to prevent civilian casualties and minimize the effects of clashes on local communities.”

Turkey currently hosts more than 2 million Syrian refugees, according to official government statistics.