North Korean leader Kim Jong Un provides guidance with Ri Hong Sop (2nd L) and Hong Sung Mu ( 2nd R) on a nuclear weapons program in this undated photo released by North Korea's Korean Central News Agency (KCNA) in Pyongyang September 3, 2017. KCNA via REUTERS

PARIS (Reuters) - France’s Emmanuel Macron discussed increased pressure and sanctions on North Korea on the telephone with U.S. President Donald Trump and Japan’s Prime Minister Shinzo Abe on Saturday, the French president’s office said.

The three leaders stressed the need for a “united and firm” reaction from the international community toward Pyongyang, Macron’s office said.

South Korea was bracing on Saturday for a possible further missile test by North Korea as it marked its founding anniversary, just days after its sixth and largest nuclear test.

The French presidency said North Korea’s “repeated provocations” were a “threat to peace and international security”. It also said Macron had expressed France’s “solidarity” with Japan.

Tension on the Korean peninsula has escalated as North Korea’s leader, Kim Jong Un, has stepped up the development of weapons, testing a string of missiles this year, including one flying over Japan.

Experts believe the Pyongyang government is close to its goal of developing a powerful nuclear weapon capable of reaching the United States, something U.S. President Trump has vowed to prevent.