Sonoma County sheriff’s detectives Thursday were looking for suspects in separate robberies that involved groups of gunmen demanding cash from people on the street.

Detectives were assessing similarities in the incidents, which took place Wednesday in different unincorporated areas of Santa Rosa, sheriff’s spokeswoman Sgt. Cecile Focha said.

In the Roseland neighborhood, two Latino men in their 20s demanded cash from a mobile ice cream vendor at about 5 p.m. Wednesday near West Avenue and Vineyard Court, Focha said in a press release. One of the men struck the ice cream man in the head with a black semiautomatic handgun, and the pair took the man’s money and fled the area in a black compact car, Focha said.

The victim was treated for head injuries at a hospital as deputies, aided by the sheriff’s helicopter, searched for the suspects, who were not apprehended.

The suspects were described as Latino males who appeared to be about 25 years old with short black hair and mustaches, Focha said. One man was shirtless and wore black pants and had a shirt tied around his waist, Focha said. The other man wore a yellow shirt and yellow pants.

At about 10 p.m. Wednesday on Santa Rosa Avenue, another man reported being robbed at gunpoint. Three men encircled him as he walked near the Palms Inn Hotel north of Todd Road, Focha said. One of the men pulled a black and silver semiautomatic handgun out of the pocket of his hooded sweatshirt and pressed the barrel into the man’s stomach as the two others circled him from behind, Focha said.

The robbers took the man’s cash, his wallet and cellphone and left on foot, she said. They dropped the cellphone, which the man used to call 911.

Two of the men were described as Latino and in their mid-20s, about 5 foot 10. One was heavyset and wore a black jacket, white T-shirt with black graffiti-style writing, dark blue jeans and dark shoes. The other man was described as medium build with a mustache and wore a dark hooded sweatshirt with the hood up, black pants and dark shoes, according to the Sheriff’s Office.

The man with the gun was described as a black man in his early 20s, about 5 foot 11 and 150 pounds, black hair, brown eyes and thin-framed glasses, Focha said. He wore a baggy hooded sweatshirt with the hood up, black baseball cap with red design, black pants and white tennis shoes.

The men ran on foot in different directions and were not found despite a search, Focha said.

Anyone with information about either case can call the sheriff’s 24-hour tip line at 565-2185. Callers may remain anonymous.