The UN Security Council will hold an emergency session today in the wake of North Korea's first successful test of an intercontinental ballistic missile (ICBM).

UN and US officials have hit out at what they described as an "escalation" by Kim Jong-Un's regime.

North Korean state media said the country's leader - "with a broad smile on his face" - described the test as a 'gift' on US Independence Day.

North Korea said the ICBM reached an altitude of 2,802km and flew 933km for about 40 minutes before landing in the Sea of Japan.

Japan's data appeared to back up these claims, with the defence ministry claiming the altitude "greatly exceeded" 2,500km.

North Korean state media claimed the missile is capable of carrying a "large, heavy nuclear warhead" that can withstand re-entry into the Earth's atmosphere.

In response to the test, US and South Korean military fired "deep strike" precision missiles into South Korean territorial waters - with officials describing it as a show of force to demonstrate US-South Korean solidarity.

US Secretary of State Rex Tillerson said the test marked "a new escalation to the threat" posed by the secretive state.

Insisting that the US "will never accept" a nuclear-armed North Korea, Mr Tillerson said: "All nations should publicly demonstrate to North Korea that there are consequences to their pursuit of nuclear weapons.

"We intend to bring North Korea's provocative action before the UN Security Council and enact stronger measures to hold the DPRK [Democratic People's Republic of Korea] accountable."

Secretary-General António Guterres, meanwhile, warned that it was a "dangerous escalation of the situation".

In a statement, a spokesperson for Mr Guterres said: "This action is yet another brazen violation of Security Council resolutions.

"The DPRK leadership must cease further provocative actions and comply fully with its international obligations."

Additional reporting by IRN