Tharoor, a former UN diplomat and Union state minister for foreign affairs, said the prime minister didn't say anything inappropriate or wrong.
Earlier in the day, Pskistan hit back at India saying Modi's allegations are baseless and wanted both neighbours to focus on resolving issues and not engage in a blame game.
Modi slammed Pakistan on Tuesday, during his visit to Leh, where he said the neighbouring country was waging a proxy war against India for it did not have a strong enough capacity for a conventional war.
Reiterating the BJP prime minister's stand, Tharoor said Pakistan is suffering in the hands of terrorism on its own soil.
Tharoor said Pakistan is suffering in the hands of terrorism it has fuelled
"I have seen the Pakistani response. We all understand that Pakistan has suffered and Pakistani civilians suffered from terrorism greatly from within that country... When you encourage, finance and nourish terrorism, it can turn back and hit you just as a monster escape the control of creators and that's what happened in Pakistan," he added.
Tharoor also criticised Pakistan of not taking action against some members of terror outfit Lashkar-e-Taiba.
Pakistan, meanwhile, violated the ceasefire in Mendhar, Poonch in Jammu and Kashmir the wee hours of Thursday. It is the seventh instance of violation at the borders in the last four days.
On Wednesday, two policemen and one civilian were killed after terrorists attacked a police convoy in Pampore in Jammu and Kashmir.