Satellite imagery from 2013 suggests that Pakistan has begun operating its third plutonium production reactor at Khushab. Imagery from 2014 shows further progress on a fourth reactor that’s still under construction.

Each of the three 50-megawatt reactors produces approximately 11.5 kilograms of weapons-grade plutonium, providing up to 35 kilograms per year. When the fourth comes online, possibly around 2016, Pakistan could be producing up to 46 kilograms a year.

And since the Khushab complex went operational in 1998, Pakistan has been shifting from highly enriched uranium to plutonium-based weapons. This is an important development if the country wants to create smaller and lighter warheads. A typical plutonium weapon requires four kilograms of Pu-239 to create a bomb, while HEU devices require 15 kilograms of U-235.

Using plutonium can mean a lighter device on a smaller and more mobile missile. More and more, Pakistan’s military planners believe they need these tactical nukes to balance India, which in April 2004 proposed a new military doctrine emphasizing rapid mobilization and offensive operations.

Pakistan’s potential tactical nukes could lower the barrier to a nuclear exchange. At least that’s what Indian officials believe.

“India will not be the first to use nuclear weapons, but if it is attacked with such weapons, it would engage in nuclear retaliation which will be massive and designed to inflict unacceptable damage on its adversary,” Shyam Saran, former Indian foreign secretary and the current chairman of India’s National Security Advisory Board, told an audience at Delhi’s Habitat Center in April 2013.

“The label on a nuclear weapon used for attacking India, strategic or tactical, is irrelevant from the Indian perspective,” Saran said.

“[A] limited nuclear war is a contradiction in terms,” he continued. “Any nuclear exchange, once initiated, would swiftly and inexorably escalate to the strategic level. Pakistan would be prudent not to assume otherwise as it sometimes appears to do, most recently by developing and perhaps deploying theater nuclear weapons.”

All that said, it’s unclear how close Pakistan is to actually deploying its tactical nukes. Likewise, India has only proposed its new offensive doctrine—it hasn’t implemented the plan. But that’s not to say tragic miscalculations couldn’t occur.

“Pakistani motivation is to dissuade India from contemplating conventional punitive retaliation to sub-conventional but highly destructive and disruptive cross-border terrorist strikes,” Saran said.

But it seems unlikely New Delhi will cave to the implicit threat. And what happens when India calls Pakistan’s atomic bluff? Assuming it is a bluff.