Syrian President Bashar al-Assad said he plans to visit North Korea's leader Kim Jong Un, Pyongyang's state media reported on Sunday, potentially becoming the first head of state to meet Kim inside the isolated country.

"I am going to visit the DPRK and meet... Kim Jong Un," Assad said, the North's state-run KCNA news agency reported, using the abbreviated version of the country's official name.

The announcement came as anticipation mounts for a historic nuclear summit between Kim and US President Donald Trump in Singapore on June 12, following a whirlwind round of diplomacy.

"The world welcomes the remarkable events in the Korean peninsula brought about recently by the outstanding political calibre and wise leadership of... Kim Jong Un," KCNA cited Assad as saying during a meeting with North Korean Ambassador Mun Jong Nam on Wednesday.

The Syrian president's office refused to comment on the report when contacted by AFP.

Pyongyang and Damascus have maintained warm ties for decades and reportedly shared a military relationship for some years, including during the ongoing Syrian civil war.

Suspicions over chemical weapons trade between Pyongyang and Damascus have been raised in the past by the UN and South Korea.

There were also widespread reports that North Korea helped Syria build a nuclear plant that was destroyed by Israeli bombing in 2007.

Both regimes have been the target of international isolation -- Pyongyang over its banned nuclear programme and Damascus for atrocities committed during the seven-year civil war.

Since coming to power in 2011, Kim has not met another head of state in North Korea. He only made his first overseas trip as a leader this year, travelling to China to meet President Xi Jinping, an ally of the reclusive regime.