In what is expected to raise eyebrows in India, a study conducted by a US think-tank has said Pakistan is on course to become the world's fifth largest nuclear weapons state by 2025. "Pakistan has a nuclear weapons stockpile of 110 to 130 warheads, an increase from an estimated 90 to 110 warheads in 2011," said a report on 'Pakistani nuclear forces 2015' by the Bulletin of Atomic Scientists released during the ongoing visit of Pakistan Prime Minister Nawaz Sharif to United States. "With several delivery systems in development, four operating plutonium production reactors, and uranium facilities, the country's stockpile will likely increase over the next 10 years, but by how much will depend on many things," it said. The report authored by Hans M Kristensen and Robert S Norris, however, said two key factors will be how many nuclear-capable launchers Pakistan plans to deploy, and how much India's nuclear arsenal grows. The authors, founding their analysis on Pakistan's performance over the past 20 years and its current and anticipated weapons deployment, have estimated that its stockpile could realistically grow to 220 to 250 warheads by 2025, making it the world's fifth largest nuclear weapon state Pakistan appears to have six types of currently operational nuclear-capable ballistic missiles, plus at least two more under-development -- the short-range Shaheen-1A and medium-range Shaheen-3. Pakistan is also developing two new cruise missiles, the ground-launched Babur (Hatf-7) and the air-launched Ra'ad (Hatf-8), it said. According to the report, there are signs that Pakistan is developing a nuclear weapon -— probably a nuclear-capable cruise missile -— for deployment on submarines.