PM Modi, speaking in Thimphu, said he arrived with a “heavy heart” after the Red Fort car blast that left 12 dead.
He assured that investigating agencies will identify and punish those responsible for the explosion.
Bhutan’s King and leaders offered prayers and condolences for the victims of the Delhi tragedy.
Prime Minister Narendra Modi stated on Tuesday that the conspirators behind the Delhi automobile explosion will not be spared as the investigative authorities will solve the case and put those involved to justice.
Modi said he travelled to Thimpu with a "heavy heart" in light of the events in Delhi during a speech at an event held at Changlimethang Stadium to commemorate the 70th birthday of Bhutan's former king Jigme Singye Wangchuck.
The prime minister claimed to have communicated with the investigative agencies looking into the explosion all throughout Monday night. On Monday night, a car exploded close to the Red Fort, killing twelve people.
"For centuries, India and Bhutan have shared a deep spiritual and cultural bond. Therefore, it was India's and my commitment to participate in this important occasion," he said.
"But today I have come here with a heavy heart. The horrific incident that occurred in Delhi last evening has deeply saddened everyone. I understand the grief of the affected families. Today, the entire nation stands with them," Modi said.
"Our agencies will get to the bottom of this conspiracy. The conspirators behind it will not be spared. All those responsible will be brought to justice," Modi said.
In front of thousands of Bhutanese at the Changlimethang stadium, King Jigme Khesar Namgyel Wangchuck offered a prayer for the victims of the Delhi explosion.
According to Indian sources, the Bhutanese leadership offered special prayers for everyone impacted by the explosions and expressed their sincere condolences for the unfortunate loss of precious lives in the Delhi disaster.
Investigators in Delhi focused on a doctor from Kashmir who was operating the exploding vehicle as they investigated the explosion as a potential terror act. It is thought that Dr Umar Nabi perished in the explosion. To prove the link, the Jammu and Kashmir authorities had already collected a sample of his mother's DNA.
The Delhi Police last night said nine people were killed in the blast and several others sustained injuries. The death toll went up to 12 with three people succumbing to their injuries, it said on Tuesday.
In his address at the event in Thimphu, Modi conveyed warm wishes of the people of India to the former king and to the people of Bhutan.
The prime minister highlighted the fourth king's transformative tenure that saw the emergence of Bhutan as a "modern nation-state" and as a constitutional democratic monarchy.
Under the fourth king's leadership, Bhutan introduced the unique concept of gross national happiness, blending economic growth with sustainability, Modi said.
The fourth king of Bhutan is a confluence of wisdom, simplicity, courage, and selfless service to the nation, Modi said.
He played a decisive role in establishing democratic systems in Bhutan and establishing peace in border areas, Modi said.
