Dozens of girls from a state-run shelter for runaways and victims of sexual abuse -- including seven who are pregnant -- have tested positive for coronavirus, Indian officials said Monday, raising fears about its spread in institutional homes.

A probe was launched after almost 60 out of 171 vulnerable girls contracted the virus at the under-18s shelter in northern India's Uttar Pradesh state. India has been grappling with a huge surge in coronavirus infections in recent weeks as the country gradually eases a strict months-long lockdown.

"We have a total of 57 minor girls who have tested corona-positive at the shelter home," Ajeet Kumar, a probation officer in Kanpur district of Uttar Pradesh, told AFP. "Many girls in such facilities have past or ongoing cases under the Protection of Children from Sexual Offences (POCSO) Act, or instances of elopement and other matters."

Seven of the girls who tested positive were also pregnant, Kumar said, adding that their pregnancies were already known before they arrived at the shelter. The girls were moved to hospitals and staff and the remaining residents were quarantined.

"The district magistrate has ordered a joint investigation over the spread of these infections in the facility," Kumar added.

The state's chief secretary on Monday issued new orders to combat the spread of the virus -- including temperature checks and limits on visitors -- in shelter homes and orphanages after the positive test results. The results also revived concerns about the mistreatment of abandoned and orphaned children in shelters after a wave of sex abuse scandals, including in Uttar Pradesh, in 2018.

The epidemic has badly hit India's densely populated major cities -- including the national capital New Delhi and the financial hub Mumbai -- with reports of hospitals being overwhelmed and patients struggling to find beds.

Chennai, in the south, went into a new lockdown from Friday because of a surge in cases.

With a population of 1.3 billion, India is the fourth worst-hit country in the world with more than 425,000 infections, official figures show.

The country reported 14,821 fresh infections on Monday.

Experts say the real number of cases is likely much higher and have called for greater testing.