Young women in Minnesota are being pressured to buy guns for criminals in exchange for cash -- a trend rarely seen across the country, authorities said on Thursday.

Women younger than 30 are being recruited by men ineligible to buy guns because of their criminal records, said Bernard Zapor, special agent in charge of the Bureau of Alcohol, Tobacco, Firearms and Explosives' St. Paul division.

"It's an anomaly for us," Zapor said, adding that there are no concrete numbers on the trend.

In most cases the women know the men. They're handed cash to buy a gun that is immediately turned over to the ex-felon, an exchange called a "straw purchase." Sometimes, they aren't paid at all.

It was among the unusual Minnesota gun trends that Zapor highlighted when he joined St. Paul Police Chief Thomas Smith and community members at a news conference calling attention to an uptick in gun violence in the city.

Authorities recovered 348 guns in St. Paul the first half of this year, a 67 percent increase from the same time last year, Smith said. Also, the number of shots-fired calls increased 42 percent this year compared with 2011.

"Those are alarming numbers," Smith said. "When that bullet leaves that gun, you can never, ever take it back."

The most recent example came Wednesday, when two men were shot and injured during an apparent midday drug deal. Smith said the city has been lucky in avoiding more serious injuries. There have been six homicides in the city this year compared with four in the same time last year.

Police and community members called on parents to talk to their kids, and for early intervention and diversion programming.

"It's going to be communities taking back their own communities," said Jeff Martin, president of the St. Paul NAACP.

St. Paul police and the ATF have long partnered against violence, but authorities said they've beefed up the partnership in the past year because of increasing violence. More officers have been deputized with federal powers, Zapor said, adding that he could not disclose their numbers.

The same partnerships are being strengthened across the state, including in Minneapolis and Duluth, Zapor said. "When it comes to gun violence, there is no second chance," he said.

Gun activity in Minnesota also is unusual for other reasons: Many of the guns used in street violence are legally purchased in the state, and criminals tend to keep guns used in crimes.

Guns are used in a crime an average of two to three years after their legal purchase, Zapor said.

The state is ripe for an increase in crime for three reasons, he said: The population of 16- to 20-year-olds is increasing; unemployment is relatively high, and inmates are being released early due to prison crowding.

Chao Xiong • 612-270-4708; Twitter: @ChaoStrib