Condemning the blasts in the US city of Boston, President Pranab Mukherjee on Tuesday said the world should unite to combat the menace of terrorism.
Extending sympathy to the families of the blast victims, the President expressed the hope that the perpetrators will be brought to justice.
He also strongly "opposed" terrorism anywhere in the world.
"Terrorism shows no respect for any boundary and the world should unite to combat this menace," the President said in Imphal.
Three persons were killed and over 130 sustained injuries when two powerful explosions rocked Boston during an annual marathon.
The two blasts occurred within seconds at a sidewalk along the route of the Boston Marathon, where thousands of people had lined up to cheer on the marathoners.
FBI special agent in charge Richard DesLauriers told reporters here that the investigation into the blasts is an "ongoing and criminal investigation that is a potential terrorist investigation."
Nearly 27,000 people were participating in the marathon which is held annually on the Patriots' Day, the third Monday of April, a state holiday in Massachusetts.