A record-breaking recent spate of missile tests by North Korea sent fears soaring that the reclusive state would soon conduct its seventh nuclear test.

US President Joe Biden held talks with allies Japan and South Korea in Phnom Penh Sunday, on the eve of a crunch meeting with Chinese counterpart Xi Jinping, whom he will press to rein in Kim Jong Un's regime.

Biden, Japanese Prime Minister Fumio Kishida and South Korean President Yoon Suk-yeol issued a joint statement condemning the recent barrage, which included an intercontinental ballistic missile.

"They reaffirm that a DPRK nuclear test would be met with a strong and resolute response from the international community," the statement said, using an abbreviation for North Korea's official name.

The trio met on the sidelines of an East Asian Summit in the Cambodian capital.

"President Biden reiterated that the US commitment to defend Japan and the ROK is ironclad and backed by the full range of capabilities, including nuclear," the statement added, using an abbreviation for the South's official name.

Biden will meet Xi on the sidelines of the G20 summit on the Indonesian island of Bali on Monday.