America's military must prepare for a “physical, violent” ground war with North Korea, according to the head of the US Marine Corps.

General Robert Neller said “everybody is going to have to be mentally prepared” for the possibility of conflict with the secretive communist state, although he made clear he was not predicting a war.

“I’m not trying to glorify this. I believe however it turns out it will be a very, very kinetic, physical, violent fight over some really, really tough ground and everybody is going to have to be mentally prepared,” he said.

The Marine Corps commandant was speaking at the Center for Strategic and International Studies, US broadcaster CNN reported.

His comments come amid heightened tensions between North Korea and the US.

Last year the pariah state conducted a series of long-range intercontinental missile tests, some of which flew over the Japanese mainland.

In September it claimed that it had successfully tested a nuclear weapon that could be loaded on to a long-range missile.

Hours after seismologists had detected an earth tremors, it said its sixth nuclear test had been a "perfect success". Experts later disputed this claim.

US President Donald Trump and North Korean leader Kim Jong-un have also exchanged a series insults.

After the Mr Kim boasted about his nuclear button, Mr Trump responded by claiming his was "a much bigger & more powerful one than his, and my Button works!”

North Korea announces intercontinental missile launch Show all 13 1 /13 North Korea announces intercontinental missile launch North Korea announces intercontinental missile launch Pyongyang residents react after the news of the successful launch of the new intercontinental ballistic missile AFP/Getty Images North Korea announces intercontinental missile launch North Korea's leader Kim Jong Un signing an order to test-fire the newly developed inter-continental ballistic missile KRT via AP Video North Korea announces intercontinental missile launch A news broadcast displays Kim Jong Un's signed document AP North Korea announces intercontinental missile launch People cheer as they watch the news broadcast announcing Kim Jong Un's order to test-fire the new inter-continental ballistic missile AFP/Getty Images North Korea announces intercontinental missile launch Residents react after the document signing AP North Korea announces intercontinental missile launch Pyongyang residents celebrate Kim Jong Un's announcement AFP/Getty North Korea announces intercontinental missile launch Cheering Pyongyang residents react AP North Korea announces intercontinental missile launch To counter North Korea's missile test, South Korea fired missiles into the East Sea The Defence Ministry/Yonhap via REUTERS North Korea announces intercontinental missile launch The Hyunmu-2 missiles firing during the drill South Korean Defense Ministry vi North Korea announces intercontinental missile launch The exercise was carried out in an attempt to counter Kim Jong Un's order South Korea Defense Ministry via AP North Korea announces intercontinental missile launch The South Korean army continue to carry out military exercises AP North Korea announces intercontinental missile launch Where K-9 self-propelled howitzers were taking part in a drill Rex Features North Korea announces intercontinental missile launch US soldiers are also present in the border city of Paju AFP/Getty Images

General Neller did not mention his leader's comments but he said that any war with North Korea would be a “different sort of fight” that would not just involve “a bunch of things flying around.”

His assessment comes just a month after he warned 300 marines stationed in Norway to prepare for a “bigass fight.”

“I hope I’m wrong, but there’s a war coming,” he told the Marine rotational force at the Norwegian Home Guard base near Trondheim in December.