Afghanistan's National Army soldiers walk out of the Indian Consulate in Herat, Afghanistan, after a clash between insurgents and security forces on Friday that killed four militants. (Photo: AP)

New Delhi: Pakistan-based terror outfit Lashkar-e-Taiba (LeT) was responsible for the terror attack at the Indian Consulate in Afghanistan's Herat province last month, the US said on Wednesday.

"LeT was responsible for the May 23, 2014, attack on the Indian Consulate in Herat, Afghanistan," the State Department said while announcing additional sanctions against LeT affiliates and leaders.

The attack on the Indian Consulate in Herat on May 23, three days before the swearing-in ceremony of Prime Minister Narendra Modi was apparently part of an effort of the LeT to derail his SAARC initiative.

Modi had invited the heads of the states of the South Asian nations including Pakistan for his swearing-in ceremony in New Delhi on May 26.

On the eve of the swearing-in ceremony, Afghan President Hamid Karzai had told an Indian news channel that LeT was responsible for the terrorist attack.

Read: Modi condemns attack on Indian consulate in Herat, Afghanistan; speaks to Hamid Karzai

The Indian consulate in Herat was attacked on May 23 by four heavily-armed gunmen, who were subsequently killed in an encounter as India attributed the pre-dawn strike to terror elements "beyond the borders" of the war-torn country.

Since its inception, LeT has been focused on carrying out major terrorist attacks inside India.

LeT claimed responsibility for the 2008 Mumbai terrorist attacks that killed at least 166 people.

In 2011, LeT was responsible for multiple terror attacks, mostly in Jammu and Kashmir, and in 2012, LeT claimed responsibility for an attack against an Indian army convoy in Kashmir that killed one civilian and injured two others, the State Department said.

LeT was designated as a terrorist organisation in December 2001.

Since the original designation, LeT has repeatedly changed its name in an effort to avoid sanctions.

I condemn the attack on our consulate in Herat, Afghanistan. Closely monitoring the situation. I have spoken to the Ambassador as well.

— Narendra Modi (@narendramodi) May 23, 2014

More specifically, LeT created Jamaat-ud-Dawa as a front organisation, claiming that the group was an "organization for the preaching of Islam, politics, and social work", the State Department said.

Al-Anfal Trust, Tehrik-e-Hurmat-e-Rasool ('Movement for Defending the Honor of God'), and Tehrik-e-Tahafuz Qibla Awwal ('Movement for Safeguarding the First Center of Prayer') are also LeT front organizations, since at least 2011, LeT has used Al-Anfal Trust to procure goods from the Persian Gulf, it said.