The firings of at least two missiles, the country's first in two months, further heighten global tensions after US President Donald Trump launched the attack that captured President Nicolas Maduro.
South Korea said peace on the Korean peninsula would be on the agenda during President Lee Jae-myung's visit to Beijing, which will include a summit with his counterpart, Xi Jinping.
The launches from the capital Pyongyang into the sea between the Koreas and Japan represent "a message to China to deter closer ties with South Korea and to counter China's stance on denuclearisation", in Seoul Institute for Far Eastern Studies professor Lim Eul-chul said.
He said North Korea also wanted to send a message that "we are different from Venezuela" - as a nuclear and military power, ready to respond with "aggressive deterrence".
Referring to North Korea's leader Kim Jong-un, Bong Youngshik, a visiting professor at Yonsei University, said: "After seeing what's happening in Venezuela right now, the person who would be most afraid is Kim Jong-un."
Seoul and Tokyo criticised the missile launches.
South Korea's presidential office said it had held an emergency security meeting and urged North Korea to cease "provocative acts that violate United Nations Security Council resolutions".
Japanese Defense Minister Shinjiro Koizumi said the launches threatened the peace and security of the neighbouring country, the region and the international community.
"Our government lodged a strong protest with North Korea and strongly condemned it," Koizumi said in a statement.
"This event does not pose an immediate threat to U.S. personnel or territory, or to our allies," US forces for the Indo-Pacific said in a statement, adding the U.S. was consulting closely with its allies and partners.
Launched about 7.50am (2250 GMT on Saturday), the missiles flew about 900km, South Korea's military said.
Japan said at least two missiles flew about 900km and 950km.
The last time Pyongyang tested a ballistic missile was on November 7.
On Saturday, Kim Jong-un called for more than doubling the production capacity of tactical guided weapons during a visit to a munitions factory, North Korea's state media reported.
In recent weeks, Kim has made a series of visits to weapons factories, as well as to a nuclear-powered submarine, and has overseen missile tests ahead of this year's Ninth Party Congress of the Workers' Party, which will set out major policy goals.
South Korea expects Beijing to play a role in promoting peace on the Korean peninsula, Lee's security adviser Wi Sung-lac said, without elaborating on details of the summit agenda.
Lee's agenda with Xi includes persuading China to facilitate dialogue with North Korea, experts say, at a time when North Korea has dismissed an outreach from Lee, who took office seven months ago.
