Assam Chief Minister Tarun Gogoi on Tuesday alleged the erstwhile National Democratic Alliance regime had supported 'secret killings' in the state during what he called the 'darkest period of its history.'

"The Bharatiya Janata Party-led NDA regime gave tacit support to the Assam Gana Parishad government under chief minister Prafulla Kumar Mahanta who perpetrated the secret killings (of ULFA kins) and that can be called the darkest period in the history of Assam," Gogoi told media persons in Guwahati.

Launching a scathing attack on BJP president Rajnath Singh for his allegation that Assam was in 'pitiable condition,' Gogoi said he was 'shedding crocodile tears.'

"The BJP, when in power at the Centre, played a negative role for Assam and not a single developmental project was taken up," he alleged.

"Contrary to Singh's belief, the law-and-order situation has improved not only in Assam but the entire North East," he claimed.

Gogoi also alleged that the NDA regime and Mahanta had 'agreed in principle' to the concept of a greater Nagaland compromising on the state's territory.