The Pennsylvania National Guard identified the slain soldiers as Sgt. Edward Koehler, 47, of Lebanon, Sgt. Brian Mowery, 49, of Halifax, and Staff Sgt. Kenneth VanGiesen, 30, of Kane.
"This tragic incident is a stark reminder of the dangers our troops face on a daily basis for the cause of freedom," Gov. Tom Corbett said in a statement. "We owe them our respect, our support and our gratitude."
All three men were riding in the same vehicle when the improvised explosive device detonated near Bagram, officials said. The other soldiers wounded did not sustain life-threatening injuries.
Koehler previously served in the Marines Corps from 1982 to 1988 and joined the National Guard in 1997, military officials said. Pennsylvania's adjutant general, Maj. Gen. Wesley Craig, said Koehler was a bugler during his time in the Marines and took pride in playing "Taps" at funerals for fallen soldiers.
"Unfortunately it is now our solemn duty to play `Taps' for him," Craig said.
In a 2005 interview with The Kane Republican, VanGiesen said he was proud to join the National Guard, like his father before him.
"If I had it to do over again, I still would do it," he told the newspaper.
VanGiesen was living in Erie where he was working with the National Guard, the newspaper reported. He had been deployed to Iraq twice and was assigned to the 131st Transportation Company, 213th Area Support Group for this mission because of his mechanical skills.
Mowery was previously been a member of the Marine Corps Reserve from 1979 to 1985, then joined the National Guard in 2000. He previously served in Kosovo.
Mowery's family released a statement requesting privacy.
Koehler's family released a statement thanking well-wishers for their support.
"Continue to pray for all of our troops and their safety," the statement said. "Their daily sacrifices must not go unnoticed."
