Nearly a month after the Boston Marathon bombings, Minnesota's two signature running marathons are continuing to study the tragedy.

But there is good news: Grandma's Marathon and the Twin Cities Marathon registrations have actually increased since the Boston bombings. Grandma's Marathon, which will be run June 22 from Two Harbors to Duluth, had 594 registrations in April, up from 476 last April and 450 registrations two years ago in April. The Twin Cities Marathon registration has "ticked up" since the tragedy in Boston, according to race spokesman Charlie Mahler. The race attracted a field of 12,200 runners last year, and registration for the Oct. 6 marathon is already 60 percent toward that total.

Three people were killed and more than 250 were injured last month when two pressure cooker bombs exploded at the finish line of the Boston Marathon. In one of the first large marathons to be held since the bombings, police reported few problems last weekend at the Pittsburgh Marathon. Officials said police were stationed at 471 locations along the race route, and that authorities checked out 17 suspicious packages — most of them unattended backpacks.

Event security changes are being considered in both of the large Minnesota marathons.

Virginia Brophy Achman, the executive director of the Twin Cities Marathon, said marathon officials are meeting with a security consultant for Medtronic Inc., the race's title sponsor, to discuss possible changes for the event. But Brophy Achman said the changes — which will not include altering the race's route — would not be publicly announced because "we want to ensure that they're effective. You don't want to connect the dots for anybody. We definitely will be looking at, 'Do we need more police presence?' " she said.

Scott Keenan, executive director of Grandma's Marathon, agreed. Keenan also said the course for the 37th annual race would remain the same, with the traditional finish at Duluth's Canal Park. The three-day race event annually draws more than 17,000 participants.

"We're not going to tell everybody our strengths so some people can find our weaknesses," Keenan said. "This is a very sensitive thing. [It's on] a need-to-know basis."

MIKE KASZUBA