CALCUTTA, India — Police arrested two Indian men accused of illegally buying mobile phone cards used by the gunmen in the Mumbai attacks, police said Saturday — the first known arrests since the bloody siege ended.

It was not immediately clear whether the two had prior knowledge of the attacks, which killed 171 people. If they did, the arrests could represent evidence of homegrown ties to the attacks and be a blow to Indian officials who have blamed the massacre entirely on Pakistani extremists.

One of the men, Tauseef Rahman, allegedly bought SIM cards by providing fake documents, including identification cards of dead people, senior police official Rajeev Kumar said Saturday in the eastern city of Calcutta.

Rahman, of West Bengal state, later sold them to Mukhtar Ahmed, Kumar said. Both men were arrested Friday and charged with fraud and criminal conspiracy.

The SIM cards were later used by the gunmen.

Police said they still were investigating how the 10 gunmen obtained the SIM cards, and declined to offer more details.

Most large Indian cities, including Calcutta, where the SIM cards were purchased, have thriving black markets for mobile phone cards and cheap phones.

Ahmed was from the Indian portion of Kashmir, the disputed Himalayan region at the root of much of the tension between India and Pakistan, Kumar said.

Indian authorities believe the banned Pakistani-based militant group Lashkar-e-Taiba, which has links to Kashmir, trained the gunmen and plotted the attacks.

Ahmed was believed to be a local police officer, according to a police official in Srinagar, Kashmir's biggest city. The official declined to be named because the matter was still under investigation.

Earlier, police said they were investigating another Indian national, Faheem Ansari, who was arrested in February in north India carrying hand-drawn sketches of hotels, the train terminal and other sites that were later attacked in Mumbai.