New Delhi, July 23 (IANS): Isak Chisi Swu, co-founder of the northeast-based militant group National Socialist Council of Nagaland-Isak-Muivah (NSCN-IM), is admitted to a city hospital and undergoing treatment for the past two weeks, doctors said on Thursday.

"Swu was admitted over severe kidney ailments and urinary tract infection. He underwent a surgery last week and is currently in the ICU," a doctor from the nephrology department of south Delhi's Fortis Hospital said on the condition of anonymity.

Refusing to divulge any further information, the doctor said until Swu recovers from his health complications completely, he will not be discharged and will be constantly under the observation of the team of doctors.

Swu was admitted to the hospital on July 5.

A source told IANS that Swu was in Delhi for the last one month and was treated for similar problems earlier also.

"Swu's two sons, who stay abroad, are also at the hospital," he told IANS.

The 85-year-old Swu, who is currently the chairman of NSCN-IM, was one of the key members in the peace talks between the government and the armed group. A ceasefire agreement was signed in 1997.