As per the sources, the terrorists are suspected to be from Lashkar-e-Taiba (LeT) and all of them are Pakistani.

Source: https://www.ibtimes.co.in/two-groups-let-terrorists-behind-army-truck-attack-jks-poonch-manhunt-underway-details-858434

On October 1, Mufti Qaiser Farooq, a former member of Lashkar-e-Taiba and a close associate of Hafiz Saeed, the mastermind behind the 26/11 attacks, was also killed in Pakistan.

Source: https://theshillongtimes.com/2023/10/21/dawood-malik-founder-of-lashkar-e-jabbar-gunned-down-in-pakistan-by-unknown-assailants/

SRINAGAR, Mar 7: Two suspected militant associates of the Lashkar-e-Taiba were arrested in Baramulla district of Jammu and Kashmir and some ammunition was recovered from their possession, police said on Tuesday.

Source: https://www.dailyexcelsior.com/2-militant-associates-of-let-arrested-in-jks-baramulla/

The Resistance Front, a proxy of the Pakistan-based terror group Lashkar-e-Taiba, was on Thursday declared a banned organisation.

Source: https://www.ndtv.com/india-news/centre-bans-the-resistance-front-proxy-of-terror-group-lashkar-e-taiba-3667948