Three banks in Washington's suburbs were held up yesterday, and in one robbery, in Gaithersburg, a teller was stabbed and critically wounded. The other two, in Northern Virginia, apparently were committed by the same two men.

The Gaithersburg holdup occurred about 8:30 p.m. at the First Women's Bank of Maryland, 13541 Clopper Rd., when a muscular man wearing a brown sweatshirt and brown nylon mask forced a teller into the bank at knifepoint as the teller was locking up, Montgomery County police reported.

The teller was then forced to open the safe, police said, and was stabbed once in the stomach after the robber obtained an undisclosed amount of money.

The teller, whose identity was withheld pending notification of relatives, was taken to the shock-trauma unit at Suburban Hospital.

The first of the Northern Virginia holdups occurred at 12:29 p.m. at a First Virginia Bank branch at 4707 Lee Hwy., Arlington. Police said the two robbers wore bandannas over their faces.

At 12:45 p.m. a second branch of First Virginia Bank, at 6220 Old Dominion Dr. in Fairfax County, was held up, and again the robbers wore bandannas, county police said.

"One man stood in the lobby with a hand in his pocket, as if he had a gun, and the other man vaulted the counter, grabbing money from several of the tellers' drawers," police spokesman Carol Kitzerow said.

The amount taken in each holdup was not disclosed.