The National Investigation Agency (NIA) on Friday arrested two key accused, including the mastermind, in Bengaluru's Rameshwaram Cafe blast case from West Bengal, a development that triggered a war of words between the BJP and the state's ruling TMC.

While the BJP alleged that the TMC has turned West Bengal into a "safe haven for terrorists", Chief Minister Mamata Banerjee said the accused were arrested due to the state police's prompt action.

The accused, Adbul Matheen Ahmed Taahaa and Mussavir Hussain Shazib, were staying in a lodge near Kolkata under assumed identities, a statement issued by the NIA said.

Taahaa was the mastermind behind the planning and execution of the blast while Shazib placed the Improvised Explosive Device (IED) at the cafe, they said.

The two accused were on the run since the explosion rocked the IT city of Bengaluru on March 1.

"It was Abdul Matheen who also worked on the escape plans and managed to evade arrest all these weeks for himself and his co-accused. The duo, along with their co-accused Maaz Muneer Ahmed, were also involved in terror cases earlier," the NIA said.

"On Friday, the anti-terror agency finally traced the duo to Kolkata, working in coordination with various other central sister agencies and state police departments of Karnataka, West Bengal, Tamil Nadu, UP, Delhi, AP and Telangana," it said.

On finding out that the "terrorists" were staying in a lodge near Kolkata under assumed identities, the NIA requested the West Bengal Police to secure the accused and the latter responded promptly, leading to a successful culmination of the search operation and apprehension of both "terrorists", it added.

Taahaa and Shazib were produced before a special NIA court in Kolkata after their arrest. The court granted three-day transit remand of the accused to the agency, the statement said.

Several customers and hotel staff members were injured, some of them grievously, in the blast that caused extensive damage to the property.

The NIA took over the probe on March 3 and had announced a reward of Rs 10 lakh for information leading to the arrest of each of the accused.

Following the arrests, BJP co-incharge of West Bengal Amit Malviya hit out at the TMC, saying the party has turned West Bengal into a "safe haven for terrorists".

"NIA detains two chief suspects in the Rameshwaram Cafe blast, bomber Mussavir Hussain Shazib and accomplice Abdul Matheen Ahmed Taahaa, from Kolkata. Both likely belong to ISIS cell in Shivamogga, Karnataka. West Bengal, unfortunately, under Mamata Banerjee, has become a safe haven for terrorists," Malviya said in a post on X.

Addressing a rally in Cooch Behar, Chief Minister Banerjee accused the BJP of spreading canards against the state.

She said, "Heard one BJP leader saying that Bengal is not safe. The accused were arrested within two hours following a prompt response by police. What about the states where you are in power?" TMC leader Kunal Ghosh also countered Malviya and said the accused were arrested with the help of West Bengal Police.

"Well done @WBPolice in connection with the Bengaluru-cafe blast arrest. Even @NIA_India has acknowledged it in their statements. Any anti-forces should be strictly dealt with. But let me ask to @BJP4India and their minions - where is this arrests made from? KANTHI. We all know which family and BJP's main leader runs illegal activities from Contai," Ghosh said in a post on X without naming anyone.

Kanthi or Contai is considered to be the stronghold of BJP leader Suvendu Adhikari and his family.

Ghosh requested the state agencies to investigate the "family's alleged role in the incident".

West Bengal Police also termed the BJP's claims "falsehood".

"WEST BENGAL POLICE EXPOSES LIES OF BJP & THEIR CHEAP TROLLS. Falsehood at its worst! Contrary to the claims made by @amitmalviya, the fact is that, two suspects in the Rameshwaram Cafe blast case have been arrested from Purba Medinipur in a JOINT operation by the West Bengal Police and the Central Intelligence Agencies. The proactive role of WBP in the matter has been officially acknowledged by the Central Agencies," West Bengal Police posted on X.

It said the state has never been a safe haven for terrorists and it will continue to remain ever-vigilant to keep its people safe.