Lalgarh (West Bengal), Aug 6 - Suspected Maoist rebels killed three activists of Jharkhand Party-Naren (JKP-N) as the West Bengal government conceded Thursday that the security operation to flush out the Left-wing extremists from this trouble-torn region has not yielded satisfactory results.

District Magistrate Narayan Swarup Nigam told IANS that the bodies of three JKP-N activists were found on the National Highway 9 near Magurai village under Binpur police station.

'All three were workers of the JKP-N. One of them was gunned down. The bodies of the other two bore injury marks inflicted with sharp weapons,' he said.

Citing police reports, Nigam said Maoists were believed to have carried out the attack.

With the recovery of these three bodies, the number of those killed by the Leftist ultras has risen to nine since the state police and central paramilitary forces began a joint operation June 18 to flush out the Maoists from the Lalgarh belt of West Bengal.

The rebels had also abducted four policemen recently. Two of them remain untraced.

As news of the killings reached the corridors of power in Kolkata, senior bureaucrats and police officers held a high-level meeting to discuss loopholes in the ongoing operation and the remedial measures.

'Initially, we received significant success in establishing the rule of the law in Lalgarh, but in the latter half of the operation the result has not been very satisfactory,' Home Secretary Ardhendu Sen told reporters after the parleys.

'As a matter of fact, we have seen that incidents of killing and abduction are taking place there.