Yellow indicates area within range of missiles. Russia United States China Britain France Note: Maps include ranges of land- and submarine-launched missiles. Source: CSIS Missile Defense Project

North Korea has drastically increased the range of its missiles. In tests last year, the nation showed that it could probably strike the United States.

North Korea

North Korea is among a number of countries that have been working to improve the accuracy and range of their missiles.

Israel India Saudi Arabia Iran Pakistan South Korea Taiwan

“We believe we’re entering a missile renaissance,” said Ian Williams, an associate director at the Center for Strategic and International Studies, who has been compiling data on missile programs in different countries.

A growing number of countries with ready access to missiles increases regional tensions and makes war more likely, Mr. Williams said. Countries are more apt to use their arsenals if they think their missiles could be targeted.

In addition, many of the missiles being developed by these countries are based on obsolete technologies, which makes them less accurate, increasing the risk to civilians. And there is a risk that missiles could fall into the hands of militias and terrorist groups.

Many of the countries that have heavily invested in missiles over the last two decades are in well-known hotspots in Asia and the Middle East. Their maximum ranges are overlaid on the map below.

Estimated maximum missile range. Saudi Arabia Israel North Korea Iran South Korea Taiwan Pakistan India The map shows ranges for countries that are capable of striking targets at distances greater than 186 miles and that have sought to increase their arsenals in the last two decades.

Countries investing in missiles are often trying to deter regional adversaries. But the effects of this arms race ripple across the globe.

North Korea is an example of the danger. Estimates of the country’s maximum missile range went from 745 miles in 1990 to more than 8,000 miles now. That’s enough to strike about half of the world, including the United States mainland. (During the same period, South Korea gained the ability to strike anywhere in North Korea.)

North Korea South Korea

Countries like Iran, North Korea and Pakistan have robust missile development programs. And the similarity of some of their missiles indicates that they have collaborated to share technology.

Pakistan began investing more heavily in its missile program in the 1990s and is believed to have also collaborated with China. By the mid-2000s, Pakistan had the ability to strike most of India, its main regional rival.

Pakistan India

India, in turn, became capable of striking anywhere in Pakistan and most of China, another regional rival, in the last two decades. India is now collaborating with Russia to develop cruise missiles.

Saudi Arabia and Israel were already able to strike Iran before 1990. But now Iran could strike back at either country, thanks in part to technology it acquired from North Korea.

Saudi Arabia Israel Iran

Additionally, both India and North Korea are working on submarine-launched missiles, which would enable the two nations to better hide their missiles to use in retaliatory strikes.

Another area of concern is militias or terrorist groups getting access to missiles.

One clear example of this happened in November, when a ballistic missile fired from Yemen reached Saudi Arabia’s capital. The missile was fired by Houthi rebels, a Shiite militia that took control of large parts of Yemen three years ago and that is backed by Iran and Hezbollah, a militant group from Lebanon.

The Arab League has accused the Houthis of firing dozens of missiles against Saudi Arabia since the kingdom began an offensive to oust the rebels in 2015.

500 miles Estimated minimum range of Houthi missile. Riyadh Saudi Arabia Yemen Territory held by the Houthis during the attack 620 miles Estimated maximum missile range. 500 miles Estimated minimum range of Houthi missile. Riyadh Saudi Arabia Yemen Territory held by the Houthis during the attack 620 miles Estimated maximum missile range. Source: Range estimate by CSIS Missile Defense Project; Houthi-held territory by the American Enterprise Institute

The weapon used against Saudi Arabia was a variation of the Scud missile.

The Scud and its variations have become some of the most common missiles in the world. Russia originally developed the Scud in the 1950s to carry weapons of mass destruction.

Korean Central News Agency

The missile played a crucial role in weapons programs of countries like North Korea and Iran. The weapons produced by North Korea are examples of how difficult it is to stop missiles from spreading.

Despite decades of sanctions, the country developed a family of ballistic missiles using lessons learned from the Scud. Some of the descendants were sold to other nations.

How a Few Missiles Become Many North Korea acquired a small number of Scud B missiles, support equipment and technology around 1980, apparently from Egypt, and worked to reverse engineer the design. Egypt Early 1980s The country has exported or planned to export its version of the Scud, the Hwasong-5, or its variations, to nearly a dozen countries, including Iran. North Korea Hwasong-5 1986 Iran Shahab-1, 1987 and -2, 1997 Syria Houthi rebels (Yemen) Iran also developed the ability to produce their own Scud versions and is suspected of passing some to the Syrian government and the Houthi militia in Yemen. Lessons from the Scud allowed North Korea to develop the No Dong missile, capable of reaching up to 930 miles. The technology was later sold to Iran and Pakistan. North Korea No Dong 1994 Pakistan Hatf-5 Ghauri 1998 775 to 930 miles Iran Shahab-3 1997/98 800 miles, low accuracy Ghadr 2007 1210 miles, more accurate Emad 2015 1,050 miles, guided The No Dong variations made in Iran enable the country to strike Israel. North Korea acquired a small number of Scud B missiles, support equipment and technology around 1980, apparently from Egypt, and worked to reverse engineer the design. Egypt Early 1980s The country has exported or planned to export its version of the Scud, the Hwasong-5, or its variations, to nearly a dozen countries, including Iran. North Korea Hwasong-5 1986 Iran Shahab-1, 1987 and -2, 1997 Houthi rebels (Yemen) Syria Iran also developed the ability to produce their own Scud versions and is suspected of passing some to the Syrian government and the Houthi militia in Yemen. North Korea No Dong 1994 Lessons from the Scud allowed North Korea to develop the No Dong missile, capable of reaching up to 930 miles. The technology was later sold to Iran and Pakistan. Pakistan Hatf-5 Ghauri 1998 775 to 930 miles Iran Shahab-3 1997/98 800 miles, low accuracy Ghadr 2007 1210 miles, more accurate Emad 2015 1,050 miles, guided The No Dong variations made in Iran enable the country to strike Israel.

“Soviet – later North Korean – Scuds might be a sort of gateway drug to a missile program, but the big story is domestic proliferation,” said Jeffrey Lewis, director of the East Asia Nonproliferation Program at the Middlebury Institute of International Studies at Monterey.

Here are some of the weapons, including an intercontinental ballistic missile, or ICBM, that North Korea developed based on the Scud design.

From a Scud to an ICBM in 20 Years Hwasong-5, 1986, 186 miles First North Korean Scud version. No Dong 1, 1994, 930 miles Enhanced Scud engine and design. Taepodong 1, 1998, 3,100 miles One enhanced No Dong engine, one Scud engine and a third, unknown motor. Taepodong 2, 2006, 6,200+ miles A three-stage satellite launch vehicle that could be used as an intercontinental ballistic missile. It uses as many as five No Dong engines on the first two stages and an unknown engine in the third stage. Hwasong-5, 1986, 186 miles First North Korean Scud version. No Dong 1, 1994, 930 miles Enhanced Scud engine and design. Taepodong 1, 1998, 3,100 miles One enhanced No Dong engine, one Scud engine and a third, unknown motor. Taepodong 2, 2006, 6,200+ miles A three-stage satellite launch vehicle that could be used as an intercontinental ballistic missile. It uses as many as five No Dong engine on the first two stages and an unknown engine in the third stage.

Trying to prevent the spread of missile technology is very difficult. But it’s nearly impossible to stop the trade in smaller parts, like guidance systems and engines, as well as human expertise. A single computer thumb drive can hold many secrets.

And, sometimes, a single piece can be the catalyst for a breakthrough: A powerful Soviet engine design that North Korea acquired is thought to be a main driver of the country’s recent advances.

Dr. Lewis added that that many counties are now learning the secrets of rocketry and how to make progressively more threatening models. India, for example, is working on a missile that could enable it to strike nearly half of the planet.

4,970 miles Estimated maximum range of a missile that India is developing. 4,970 miles Estimated maximum range of a missile that India is developing.

The rising threat of missile proliferation has sparked new control efforts by the Missile Technology Control Regime, a group of 35 countries that seeks to restrict exports of missiles and their components.

The group in a recent statement highlighted the “critical importance” of its work for addressing the rapid changes in how weapons are developed and transferred.