Amid Israel’s wide-ranging strikes on Iran in the early morning hours of June 13, targeting the country’s nuclear facilities and top military leaders, it is important to unveil countries with nuclear weapons, and they are less than ten.

A nuclear weapon is an explosive device capable of high-level destruction usually driven by force from nuclear reactions, either fission (fission or atomic bomb) or a combination of fission and fusion reactions (thermonuclear weapon). The explosion produced by this reaction is called nuclear explosion and its effect can be devastating, sometimes far more than imagined.

A single nuclear weapon, according to experts, can destroy a whole city and kill most of its inhabitants. The bombings of Hiroshima and Nagasaki in Japan during World War II by America is an example of the fatality that nuclear bomb can cause.

Iran does not have nuclear weapons but Israel struck in a bid to prevent Tehran from building atomic weapons, as Iran was said to have a uranium enrichment program, which is a prerequisite for developing nuclear bombs.

Iran responded with retaliatory drone strikes on Israel, according to Israel’s military, hours after Prime Minister Benjamin Netanyahu said he had begun an operation aimed at rolling back Iran’s “threat to Israel’s very survival.” In a video address, Netanyahu said Iran had taken steps in recent months to weaponize enriched uranium and was on the cusp of developing a nuclear weapon within months to a year.

“If not stopped, Iran could produce a nuclear weapon in a very short time,” Netanyahu said in the address, which came shortly after Israel confirmed the overnight attack.

On the heels of Israel’s strikes on Iran over its nuclear program, here’s a look at which nations have nuclear weapons.

NINE NATIONS WITH NUCLEAR WEAPONS

Nine countries currently possess nuclear weapons: the U.S., Russia, France, China, the United Kingdom, Pakistan, India, Israel, and North Korea.

Israel has neither acknowledged nor denied the existence of their nuclear arsenal, according to the nonpartisan Arms Control Center, though estimates of their stockpile from various nonproliferation and watchdog groups said they have about 90 nuclear weapons.

In total, the scientific research non-profit Association of American Scientists estimates the global nuclear stockpile is approximately 12,241 nuclear warheads. The association says the exact number of nuclear weapons is an estimate, as each nuclear-armed nation considers its stockpile a closely held national secret, and most provide essentially no information about their cache of weapons.

The association, which was founded in response to the devastating use of nuclear weapons by the U.S. on Japanese cities Hiroshima and Nagasaki during WWII, says there are roughly 9,614 in military stockpiles capable of use by missiles, aircraft, ships and submarines.

Belarus, Kazakhstan, Ukraine and South Africa all once had nuclear weapons at one point, but in 1991 the nations gave up their stockpiles and joined the Nuclear Nonproliferation Treaty.

Does Iran have nuclear weapons?

No, Iran does not have nuclear weapons, but it does have a uranium enrichment program, which is a prerequisite for developing nuclear bombs.

Tehran says it pursues nuclear technology for peaceful purposes, such as using non-military nuclear technology for medicine, agriculture and energy, and has long denied accusations by Western powers that it is seeking to develop nuclear weapons.

Iran has a long history of engaging in secret nuclear weapons research in violation of its international commitments, according to the Council on Foreign Relations, and its uranium enrichment program has long raised concerns among many nations and nuclear watchdogs that it could enable the creation of nuclear arms.

Which country has the most nuclear weapons?

The U.S. and Russia possess approximately 87% of the world’s total nuclear weapon stockpile, according to the Association of American Scientists, with 83% of their stockpiled warheads available for use by the military.

In contrast, the seven other nations with nuclear weapons possess a dramatically reduced number of weapons, ranging in the hundreds to a few dozen, while the U.S. and Russia each possess caches estimated to exceed 5,000.

The world’s nuclear stockpiles have been decreasing over the past few decades as non-proliferation agreements and treaties took hold after the end of the arms race during the Cold War. However, the Association of American Scientists says the pace of reductions is slowing. While the U.S., France and Israel are either reducing or maintaining their inventories, several other nations are increasing theirs. That includes China, India, North Korea and Pakistan, according to the Arms Control Association.

Additional reports by usatoday.com