A deadly car blast in India’s capital late Monday that killed at least eight people and injured several others, occurred close to the historic Red Fort in New Delhi

Authorities have not determined the cause of the blast, but senior police officials told The Associated Press that a case has been registered under anti-terrorism laws. The officials spoke on condition of anonymity because of the sensitivity of the case.

Prime Minister Narendra Modi, who was on a scheduled visit to Bhutan on Tuesday, said investigators would “get to the bottom of this conspiracy,” as he vowed for justice.

According to Modi in a statement on Tuesday morning: “The horrific blast in Delhi last evening has deeply pained everyone. India stands with those who have suffered. I assure everyone that the agencies will get to the bottom of the entire conspiracy. All those involved will be brought to justice and the conspirators won’t be spared.”