The attacks took place on Wednesday when the ISKCON temple in Watford in UK was holding prayers for victims of war and terror with a human chain.
"It is sad that at almost exactly the same moment when children were holding hands to pray for victims of terror at 2 pm in our temple in UK, terrorists were exploding bombs in our temple in India to kill and maim," said Gauri Dasa, President of the Bhaktivedanta Manor ISKCON temple in Watford which is hosting the largest Hindu festival outside India.
"We had organised this prayer to show our solidarity to all those who are suffering, but the terrorist agenda seems to disregard all humane considerations."
Costumes, bazaars, plays, singing, dancing, multimedia shows, meditation walks and other shows mark the festival, which attracts over 75,000 people over two days.
The highlight of the festival is a human chain to pray for the victims of terror and war.
Hindu Forum of Britain secretary general Ramesh Kallidai also condemned the attack, saying "Terrorism is a real challenge for countries like India, Britain and the USA."
Calling the attack, "deplorable and shameful", he said the perpetrators "targeted a peaceful community offering prayers to God" and added that " the international community need to rally behind India in its fight against terror."