SEOUL--North Korea is marking a key state anniversary Friday with calls for stronger loyalty to leader Kim Jong Un, but there was no word on an expected military parade to display new weapons amid heightened animosities with the United States.

The 110th birth anniversary of Kim’s late grandfather and state founder, Kim Il Sung, comes after North Korea conducted a spate of weapons tests in recent months, including its first full-range intercontinental ballistic missile launch since 2017. Experts say North Korea aims to expand its weapons arsenal and ramp up pressure on the United States amid long-stalled nuclear diplomacy.

“Let’s work harder in devotion to our respected comrade Kim Jong Un and on that path ultimately realize the dreams of our great president (Kim Il Sung) to build a powerful socialist state,” the North’s state-run website Uriminzokkiri said in a commentary.

The North’s main Rodong Sinmun newspaper said North Korea is revering Kim Il Sung as “eternal president” under the “outstanding leadership of comrade Kim Jong Un.”

Kim Il Sung’s birthday is the most important national holiday in North Korea, where the Kim family has ruled under a strong personality cult since the nation’s founding in 1948. Kim Jong Un is the third generation of his family to rule North Korea after his father died in late 2011.

Kim has pushed ambitiously to advance his nuclear arsenal while simultaneously reviving the economy. But a mix of pandemic-caused hardships, U.S.-led sanctions and his own mismanagement have caused a massive economic blow in what’s become the toughest moment of his decade in power.

North Korea often marks key state anniversaries with huge military parades featuring newly built missiles. State media said Kim Il Sung’s birthday will be celebrated with fireworks, a dance party and a performance, but didn’t mention a military parade.

NK News, a North Korea-focused news outlet, said its sources in Pyongyang reported hearing jets and helicopters flying low over the city center shortly after midnight Thursday--a possible indication that a nighttime military parade was taking place. South Korea’s Defense Ministry said it had no immediate information to share with the media on a possible military parade in North Korea.

After North Korea’s ICMB test last month, South Korean and U.S. officials said North Korea could soon launch fresh provocations like an additional ICBM test, a banned launch of a rocket to put a spy satellite into orbit, or even a nuclear bomb test that would be the seventh of its kind.

South Korea’s military said recently it detected signs that North Korea is rebuilding tunnels at a nuclear testing ground that it partially dismantled before it entered now-dormant nuclear talks with the United States in 2018. Some experts say North Korea will likely perform a nuclear test after U.S. and South Korea militaries begin their annual drills, which the North views as an invasion rehearsal, next week.

“I think they’ll carry out a nuclear test once it finishes restoring its nuclear testing facility,” said Moon Seong Mook, an analyst with the Seoul-based Korea Research Institute for National Strategy. “There is no reason for them to bring back its testing ground if they don’t plan to use them for a bomb test.”

Sung Kim, the top U.S. official on North Korea, is to visit South Korea next week for talks on the international community’s response to the North’s recent missile tests. Sung Kim said last week the North Korean birth anniversary could pass without any further potential provocation like a nuclear test of another missile launch.

North Korea has recently resumed its trademark harsh rhetoric against its rivals. One of its international affairs commentators labeled President Joe Biden as “an old man in senility,” while Kim’s powerful sister, Kim Yo Jong, called South Korea’s defense minister “a scum-like guy” and threatened to annihilate South Korea with nuclear strikes.

Some experts say the ongoing brinkmanship is also likely motivated by domestic politics, as Kim Jong Un doesn’t otherwise have significant accomplishments to flaunt to his people since his summitry with then-President Donald Trump aimed at winning badly needed sanctions relief collapsed in 2019. Last year, Kim acknowledged North Korea was facing its “worst-ever situation.”

North Korea has so far shunned millions of COVID-19 vaccine shots offered by the U.N.-backed COVAX distribution program, possibly reflecting an unease toward accepting international monitors. But some analysts say country may still seek help from China and Russia to inoculate workers, officials and troops in border areas as it proceeds with a phased resumption of trade.

Geneva-based GAVI, the lead manager of COVAX, said recently it has no doses committed to North Korea after moving to needs-based vaccine allocations in 2022. North Korea and Eritrea are the only U.N.-member countries not to have rolled out vaccines.