Indian police on Tuesday evening said they have arrested six men alleged to be plotting terror attacks across major cities of the country.

The attacks were allegedly being planned from Pakistan and were "meant to target congregations during the upcoming festive season," said Neeraj Thakur of the Delhi Police Special Cell, the arm responsible for investigating terrorism and organized crime-related cases.

The Hindu festival of Durga Puja takes place in roughly a month's time, with the year's biggest festival Diwali celebrated on November 4. 

The two of the suspects arrested were believed to have gone to Pakistan via Oman where they received training in using explosives and firearms, he told reporters at a press conference.

"In Pakistan, they were kept at a farmhouse for 15 days during which they were trained in firearms," Thakur later told Indian broadcaster NDTV.

The arrests were made during a morning raid in a multi-state operation, he said.

Two men were arrested in the capital New Delhi, three were held in neighboring Uttar Pradesh state, and one was caught in the northern state of Rajasthan.

Police also said they recovered a cache of weapons and explosives, including IEDs, during the operation.

Authorities also said that the brother of fugitive underworld don Dawood Ibrahim, Anees, was responsible for coordinating the attacks.

This included recruiting, finance, transport, and other logistical aspects using his contacts, the Times of India newspaper reported.

Ibrahim, a designated global terrorist by India and the US, was thought to be living in Pakistan, a claim that Pakistani authorities have denied.

Indian authorities have long accused Pakistan of aiding and abetting terror activities within its borders. Islamabad has repeatedly rejected these allegations.