House Minority Leader Nancy Pelosi on Thursday defended so-called sanctuary cities, even after the shooting death of a San Francisco woman at the hands of an illegal immigrant set free under the policy.

While the Department of Homeland Security has blamed San Francisco's policy for that death, Pelosi said she blames Congress for failing to pass immigration reform.

"I support the sanctuary" policy, said Pelosi, a Democrat who represents San Francisco. She was referring to a broad policy implemented by some local governments that rejects federal immigration laws. In San Francisco's case, the city refused to cooperate with federal requests to keep the shooter detained, or to inform the government once he was released.

"We had this terrible case," Pelosi said, making reference to the death earlier this month of Kate Steinle, 32. "Our hearts and prayers go out to the family."

Steinle was shot to death on a San Francisco pier by Juan Francisco Lopez-Sanchez, a felon and illegal immigrant who had been deported five times but was released by city law enforcement officials despite federal orders to confine him.

Pelosi said Congress should have passed a comprehensive bill addressing illegal immigration, "which is the answer to many of the questions on this subject."

Pelosi said she does not support a GOP proposal to implement mandatory prison sentences for deported illegal immigrants to return to the United States.

Instead, she said she backs "a graduated mandatory sentence for repeated offenses," adding, "I think that is probably a better model than the model put forward by Republicans."