Las Vegas schools are planning to reopen within weeks as anger and concerns grow over US student mental health and a possible surge in suicides since they closed due to Covid-19 last March.

Nevada's Clark County, which includes Las Vegas and the fifth-largest school district in the country, has recorded 19 suicides among students since the school closures.

That figure is "more than double the nine the district had the entire previous year," the district's press office told AFP, without directly tying the trend to reopening schools in the western state. 

A large number of complex factors contribute to suicides, which can never be explained by a single cause, experts warn.

But studies have shown that the pandemic has particularly impacted more vulnerable parts of society, including among out-of-school youths. And an increase in psychological disorders have coincided with the coronavirus pandemic and associated lockdowns.

As attitudes toward lockdowns during the Covid-19 pandemic have grown more politically polarized in the US, opponents of school closures have amplified the voices of victims' families and some mental health experts in warning about their impact on child wellbeing.

Former President Donald Trump repeatedly tried to pressure schools into reopening, while Centers for Disease Control and Prevention ex-director Robert Redfield cited "increases of adolescent suicide" among the costs of children missing school at a briefing last July.

"When we started to see the uptick in children taking their lives, we knew it wasn't just the Covid numbers we need to look at anymore," Clark County superintendent Jesus Jara, who has been lobbying for months to reopen schools, told the New York Times.

"We have to find a way to put our hands on our kids, to see them, to look at them. They've got to start seeing some movement, some hope."

Alarmed by mental health concerns, the district set up an alert program last summer to identify at-risk students.

The scheme included sifting through iPads given to students to scan for key words related to suicide or mental health concerns, and prompted more than 3,100 alerts between June and October.

This caused the district to introduce 24-hour monitoring in November, according to the New York Times.

No date has been formally set for Las Vegas schools to reopen. But the district has been given the green light to proceed subject to health regulation compliance.

The first students, including younger children, could be back at their desks in weeks.