GENEVA (AP) — The U.N. human rights chief said Monday she was "alarmed" that migrant children are still being held in centers in the United States and Mexico and warned that climate change has become an unprecedented threat to human rights worldwide.

In her introductory address for the start of the Human Rights Council's latest session, Michelle Bachelet aired concerns from unlawful killings and injuries of Palestinians by Israeli security forces to India's actions against Kashmiris,

But the rights chief, who is a former president of Chile, put her main focus on environmental concerns — calling variously for greater participation in the fight against climate change by businesses and greater space for environmental activists to express their views.

"We are burning up our future — literally," Bachelet said. "The world has never seen a threat to human rights of this scope. This is not a situation where any country, any institution, any policymaker can stand on the sidelines."

Alluding to a Swedish teenage climate campaigner, the human rights chief decried "verbal attacks on young activists such as Greta Thunberg and others."

Looking past personal criticism against her from Brazilian President Jair Bolsonaro in recent days, Bachelet also reiterated her concerns about the "drastic acceleration of deforestation of the Amazon."

"The fires currently raging across the rainforest may have catastrophic impact on humanity as a whole," Bachelet said, "but their worst effects are suffered by the women, men and children who live in these areas, among them, many indigenous peoples."

She urged authorities in Brazil, as well as Paraguay and Bolivia, to ensure "longstanding environmental policies" are carried out, "thus preventing future tragedies."

Last week, Bolsonaro praised the 1973 military coup by Gen. Augusto Pinochet in Chile that led to Bachelet's father's death a year later in captivity. Asked by The Associated Press to respond to those comments, she declined to comment.

As for migrants' rights in Central America and on the U.S.-border, Bachelet said she was concerned that policies by the United States, Mexico and others in the region "are putting migrants at heightened risk of human rights violations and abuses."

"Notably, I am alarmed that migrant children continue to be detained in centers in both the U.S. and Mexico, contravening the best interests of the child, which is a fundamental tenet of international law," she said, She said at least 35,000 asylum-seekers have been "pushed back" to Mexican border areas to wait for their hearings this year.

The Trump administration pulled the United States out of the council last year, accusing it of an anti-Israel bias and denouncing some member states that Washington says are repeat rights violators.

On other issues, Bachelet flagged her concerns about "extensive arrests and police action" in the run-up to Sunday's local elections in Moscow. She joined calls for "investigations into the allegations of excessive use of force by the police."

She expressed concerns about Kashmir, including restrictions on internet communications and peaceful assembly, and the detention of local political leaders and activists, and said she had "appealed particularly to India to ease the current lockdowns or curfews; to ensure people's access to basic services" and ensure due process rights.

As for Israel, whose government has repeatedly accused the council of anti-Israeli bias, Bachelet decried "very high levels of settler violence, and Israel's failure to adequately protect Palestinians from such attacks or hold the perpetrators to account."

She cited a recent increase in demolitions of homes under an Israeli zoning and planning framework "which discriminates heavily against Palestinians."

"I continued to be alarmed by reports of unlawful killings and injuries of Palestinians by Israeli security forces across the entire occupied territory, accompanied by a lack of full accountability for instances of possible excessive use of force," she said.

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