The United Nations high commissioner for human rights, Michelle Bachelet, is sending teams to Italy and Austria to look into protection of migrants after what she called an “alarming escalation of attacks” against asylum seekers and Roma people.

In her maiden speech to the UN human rights council on Monday, in Geneva, Bachelet said: “Italy’s decision to close its sea ports, denying entry to NGO rescue ships, had serious consequences on the most vulnerable. Even though we are seeing a big drop in the numbers of coming from Libya over the past 12 months, the numbers of those who died during the crossing is higher in the first six months of 2018 than it was.”

The approach adopted by Italy’s interior minister, Matteo Salvini, whose League party is in coalition with the populist Five Star Movement, has involved the government launching a series of anti-immigrant policies, including preventing migrant rescue ships from docking in Italian ports.

Anti-racist groups in Italy have warned of a dangerous acceleration in attacks on immigrants after14 shootings, two murders and 56 physical assaults were recorded in the three months since Salvini entered government in June.

The Italian interior minister, Matteo Salvini. Photograph: Daniel Dal Zennaro/EPA

Opposition politicians, charities and NGOs have accused Salvini of creating a climate of hate following the attacks, which have coincided with an anti-migration drive that has included a vow to expel Roma people.

“We do not accept lessons from anyone, let alone from the UN,” said Salvini, calling the UN “misinformed” about the situation in Italy. “They should first focus on other members where fundamental human rights are being violated every day.”

Salvini was placed under investigation by Italian prosecutors from Agrigento, Sicily, for kidnapping, relating to his refusal to allow 177 migrants on board the coastguard ship, Ubaldo Diciotti, to disembark.

During her speech, Bachelet – who is a former president of Chile – warned about abuses worldwide, citing among others the “deeply disturbing allegations of large-scale arbitrary detentions of Uighurs and other Muslim communities, in so-called re-education camps across Xinjiang”, and the Trump administration’s “unconscionable” separations of migrant families.

Bachelet voiced concern over the 500 migrant children in the United States taken away from their parents who have not yet been returned by authorities. She denounced the announcement by Donald Trump’s administration last week that it would sidestep a court agreement limiting detention of migrant children to 20 days. In July, the UN completed an agreement to handle the global flow of migrants which was boycotted by the United States, under orders from the Trump administration.

The US withdrew from the UN human rights council in June, accusing the body of “hypocrisy” and anti-Israel bias.

Bachelet, who is the daughter of a general who opposed Augusto Pinochet’s overthrow of Chilean president Salvador Allende in 1973, and assumed office on 1 September, called for a new institution to “collect evidence with a view to future prosecution of crimes against Muslim Rohingya in Myanmar”.

She urged the Saudi-led military coalition in Yemen to show “greater transparency in its rules of engagement and hold to account perpetrators of airstrikes on civilians”, and voiced alarm at anti-migrant violence in Germany, raising concerns of recent unrest in Chemnitz, where 2,500 people have marched in a far-right demonstration after a German man died following a fight with two Afghans.