Actions could include ICBM and spy satellite launch amid signs of activity at key launch sites.

US President Joe Biden is due to meet South Korean President Yoon Suk-yeol and Japanese Prime Minister Fumio Kishida at Camp David on August 19, as he looks to enhance ties between Seoul and Tokyo amid nuclear threats from North Korea and China’s increasing assertiveness.

North Korea has criticised deepening military cooperation among the three nations as part of an alleged effort to set up an “Asian version of NATO”. China, a key Pyongyang ally, has made similar accusations.

Yoo Sang-bum, a member of the South Korean parliament, told reporters after meeting the chief of the National Intelligence Service on Thursday that North Korea was planning “provocations”. Support vehicles for a potential missile launch had been seen in areas near Pyongyang, while frequent movements of propellants from the liquid fuel factor had also been detected, he said.

The reclusive state could also attempt another spy satellite launch at the end of August or early September after the failure of their first effort in May, Yoo said.

There was a chance it could take place on September 9 when North Korea celebrates the 75th anniversary of its founding, he added.

North Korean leader Kim Jong Un, who included a spy satellite among a list of key weapons requirements, has already made a second launch attempt a priority after the first was deemed the “gravest failure“.

North Korea, which sealed its borders with the COVID-19 pandemic, is also opening up, according to South Korean intelligence.

Russia agreed on broad defence cooperation when the Russian defence minister Sergei Shoigu met Kim last month and watched a military parade with him in Pyongyang, Yoo quoted South Korean intelligence as saying. Chinese officials also attended the parade, and South Korean intelligence says Pyongyang is also moving ahead with the opening of the border with China.

“The National Intelligence Service is anticipating that Russia and North Korea will speed up their defence cooperation and it is closely tracing movements” to spot any possible Russian transfer of nuclear missile technology to Pyongyang, Yoo said.

The United States has accused North Korea of providing weapons to Russia for its invasion of Ukraine, and on Wednesday announced new sanctions against three entities that it said were involved in arms deals between the two countries.

Pyongyang and Moscow have denied arms transactions.

Since the start of 2022, North Korea has test-fired about 100 missiles as Kim accelerates the expansion of his country’s banned nuclear and ballistic missiles programme.