San Francisco mayoral candidate Mark Leno laid out an ambitious plan Friday that he claims can end the city’s homelessness problem by 2020.

At a news conference in U.N. Plaza, which for years has been a backdrop for the city’s homelessness and open-air drug-use problems, Leno laid out a multipronged approach that begins with keeping at-risk people housed. He was joined by BART Director Bevan Dufty, an ex-supervisor and the city’s former “homeless czar,” who has endorsed Leno’s campaign.

That, Leno said, would involve increasing the city’s investments in “rental and legal assistance to stop unfair, unjust evictions from the Ellis Act. I’ll take speculators who are buying buildings and evicting all tenants illegally to court.”

Leno also pledged to “immediately” move at least 1,000 people off the streets and into single-room occupancy hotels. Citing figures from the city’s Department of Building Inspection, Leno said there were as many as 1,500 vacant SRO units that could be used for housing.

“We don’t have to build those units. They’re there,” Leno said. “I will bring the owners of those (SRO) buildings together with the mayor’s office to identify how we can get those who are homeless into those units and provide the supportive services they’ll need to keep themselves successful in their housing.”

He estimated it would cost the city about $1.2 million annually for every 50 people housed in SROs.

The plan did not include further details about how much his proposals might cost, but Leno said shifting the city’s budget priorities would make the plan feasible. The city could spend less on street cleaning, he said, once more homeless people are housed, because there would be less trash, human waste and needles on the streets, he said.

His plan also calls for expanding the city’s existing homeless shelters and Navigation Centers and creating a so-called mental health justice center to address those on the streets suffering from mental illnesses.

In terms of Leno’s aggressive timeline, “I’m not sure if it’s possible or not, but we can certainly do better, and it’s certainly going to take more investment,” said Jeff Kositsky, who leads the city’s Department of Homelessness and Supportive Housing. Kositsky declined to weigh in on the specifics of Leno’s plan.

— Dominic Fracassa

Help, or get out of the way: San Francisco Mayor Mark Farrell asked federal law enforcement officials this week to cooperate — not hinder — with the city on its efforts to open the nation’s first safe-injection site for injection drug users.

In a letter to U.S. Attorney General Jeff Sessions, Farrell wrote that the ultimate goal of such sites — “to save lives” — requires “partnership and support from the federal government, rather than impediment.”

Citing the need to address the national opioid epidemic, the spread of infectious diseases from dirty needles and the risks of overdose deaths, Farrell asked the federal government to “turn their attention to supporting rather than prosecuting those who are trying to save lives.”

Whether Farrell will persuade the federal government to back off seems unlikely.

Katherine Pfaff, a spokeswoman for the federal Drug Enforcement Administration, said in an email that safe-injection sites plainly “violate federal law. Any facilitation of illicit drug use is considered in violation of the Controlled Substances Act and, therefore, subject to legal action.”

— Dominic Fracassa