Reported armed robberies in the District of Columbia have increased more than 40 percent this year over the same period last year, and robberies of financial institutions have nearly doubled during the same time, D.C. police officials reported yesterday.

There were three robberies of financial institutions yesterday. At 10:49 a.m., a man robbed D.C. National Bank at 1090 Vermont Ave. NW after he presented a note to a teller. Fifteen minutes later, a man of about the same description walked into Columbia Federal Savings and Loan at 1700 Pennsylvania Ave. and demanded money. He fled with an undetermined amount.

Shortly after 1 p.m., two men, one armed with a handgun, robbed the First American Bank at 502 23rd St. NW.

"I'm deeply concerned about armed robberies," D.C. Police Chief Maurice T. Turner said. "A lot of it the increase , I attribute to narcotics. But there are also other factors. There are a lot of guns on the streets. When they robbers don't use guns, they use knives. There's a lot of unemployment."

Armed robberies reported since Jan. 1 total 3,564, an increase of 1,026 over the 2,538 reported the same period last year, police said. Robberies of financial institutions increased from 37 the first eight months of last year to 69 for the same period this year.

Officials said the 28-member robbery squad is averaging 16 armed robberies reports a day.

Alfonso Gibson, head of the criminal investigations unit, said the increase in armed robberies has swamped robbery squad detectives who are averaging assignment of 17 robberies a month.

Turner said one of the things he is doing is evaluating the department's resources to find out how he "can bolster" the robbery squad.

He says the robbery squad has a 24 percent closure rate. "Even with the lack of men, we are doing very well in that category," he said.