Nine people, including two students, have died in three bombings in the United States, the AFP news agency said today.

The spate of gun violence in northern California and Iowa comes less than 48 hours after a gunman opened fire at a Chinese New Year celebration in Los Angeles, killing 11.

Two shootings were reported at a farm in Half Moon Bay, northern California, south of San Francisco. Seven people died and three were seriously injured.

There has been no official confirmation of the death toll, but the San Mateo County Sheriff tweeted that it was an incident. "The suspect is in custody. There is no ongoing threat to the community at this time," the sheriff's office tweeted.

One person died and three were injured at the Mountain Mushroom Farm, ABC7 reported, citing law enforcement. Three people died at a nearby Tucking-Soil Rice farm, the broadcaster said on its website. He revised the count and reported that seven people had died in these two shootings.

California Governor Gavin Newsom, who was in Monterey Park where Saturday's shooting took place, took to Twitter after news of the latest incident. "At the hospital meeting with victims of a mass shooting when I get pulled away to be briefed about another shooting. This time in Half Moon Bay. Tragedy upon tragedy."

Another shooting was reported in Des Moines, Iowa. The event took place at Starts Right Here, which runs a mentoring program for at-risk youth. Two students were killed and three people were injured, two seriously.

Des Moines police said in a statement that two teenagers, ages 18 and 16, died after suffering serious injuries at a hospital. William Holmes, the 49-year-old co-founder of Right Here, is in dire straits.

The back-to-back events come against a backdrop of a dramatic increase in gun violence in the United States and a heated debate over easier gun access.

Last year, there were 647 shootings, in which at least four people were shot or killed by the gunman, according to the Gun Violence Archive website.

More than 44,000 people died from gunshot wounds in 2022 in the United States, more than half of them were suicides.