US president Donald Trump summoned the entire Senate to attend a White House meeting tomorrow to discuss the growing danger posed by North Korea.

The decision to call the unusually large gathering involving all 100 senators is rare, but comes amid growing concerns surrounding North Korea’s development of nuclear weapons and missile technology.

North Korea’s military staged a “large-scale artillery drill” today to mark the founding of the country’s army 85 years ago.

The long-range artillery drills were reportedly conducted near Wonsan, along North Korea’s east coast.

“Our military is closely monitoring the North Korean military’s movements,”  the South Korean Joint Chiefs of Staff said in a statement.

North Korea’s military activity was matched by the US today, when the Trump administration ordered U.S.S. Michigan, a submarine armed with Tomahawk cruise missiles, to the port city of Busan in South Korea.

The decision to station the submarine in Busan reflects the heightened tension between the US and North Korea.

Tomorrow, senators will be briefed on the situation between the two countries by the top US security officials, including secretary of state Rex Tillerson, secretary of defense Jim Mattis, director of national intelligence Dan Coats and general Joseph Dunford, chairman of the joint chiefs of staff.

“By 2020, if nothing changes inside of North Korea, they’ll have the technology, they’ll have a breakthrough, to develop an ICBM [intercontinental ballistic missiles] that can reach America. I hope this president will say that’s a non-starter,” Republican senator Lindsey Graham said.

Yesterday Trump told ambassadors from UN Security Council member states that North Korea is a “big world problem” and that “additional and stronger sanctions” against it are necessary.

On Friday, Tillerson will chair a security council foreign ministers’ meeting in New York. North Korea will feature heavily in discussions.

“This meeting will give the security council the opportunity to discuss ways to maximise the impact of existing security council measures and to show their resolve to response further provocations with appropriate new measures,” said Mark Toner, state department spokesman.

The briefing will take place tomorrow at 7pm London time.