A report released by the group, Peace Now, said more than 340,000 settlers live in the West Bank, more than triple the number who lived there 20 years ago when the 1990s Oslo Accords were signed.
More than half of the new settlers moved to three settlements, and 64 percent of the growth is taking place in regions that could remain in Israeli control in potential land swaps with Palestinians, the report said.
Some 60 percent of the housing units currently under construction are in more isolated settlements. The longer Israel develops isolated areas like these, the more difficult a two-state solution would be, Peace Now concluded.
Peace talks between Israeli and Palestinian officials took place in July, but the outcome of the discussions have been kept mostly secret.
Palestinian President Mahmoud Abbas was in Europe this week to push for an Israeli settlement freeze, and Israeli Prime Minister Binyamin Netanyahu is scheduled to go travel Europe next week to meet with U.S. Secretary of State John Kerry to discuss peace negotiations, the Los Angeles Times reported.