The US and South Korea have carried out a live-fire exercise in response to North Korea's launch of an intercontinental ballistic missile capable of striking the American mainland.

The display of firepower came as experts said the trajectory of the rocket fired by Pyongyang, which landed in the Sea of Japan, indicated major cities across the US were now within range.

Image: Kim Jong Un said the US is now within range of North Korea's missiles

North Korean leader Kim Jong Un, who personally supervised the launch of the missile on Friday night, said it served as a "stern warning" for the US, according to the North's official KCNA news agency.

He claimed it brought the whole of the US within firing range that could be hit "at any place and time".

It is the second ICBM launch in less than a month by the North, despite international efforts to curb the development of missile technology by the nuclear-armed authoritarian state.


Image: Experts say the missile launched by North Korea is capable of reaching major US cities

US President Donald Trump said: "By threatening the world, these weapons and tests further isolate North Korea, weaken its economy, and deprive its people.

"The United States will take all necessary steps to ensure the security of the American homeland and protect our allies in the region."

:: Nuclear missiles within Kim's grasp

As well as conducting the live-fire exercise, South Korea has also said it will push ahead with the deployment of four additional units of the US THAAD anti-missile defence system.

This in turn has led China, the North's main ally, to express serious concerns, arguing it would make the situation "more complex".

The country's foreign ministry said it opposed Pyongyang's launch activities, but added: "At the same time, China hopes all parties act with caution, to prevent tensions from continuing to escalate, to jointly protect regional peace and stability."

Image: North Korea's leader Kim Jong Un personally oversaw the launch

The missile test came a day after the US Senate approved a package of sanctions on North Korea, Russia and Iran.

The White House has said Mr Trump is ready to sign off the measures.

The sanctions are likely to include measures aimed at Chinese financial institutions that do business with North Korea.