Syria and North Korea might be two of the most embattled countries in the world right now. But in the face of increasing pressure from the United States, the two nations are reaffirming their friendship.

North Korea's state-run Korean Central News Agency (KCNA) reported Tuesday that leader Kim Jong Un had received a message from Syrian President Bashar al-Assad marking the anniversary of the birth of Kim's grandfather and North Korea founder, Kim Il Sung, who died in 1994.

The message said the two nations were "conducting a war against big powers' wild ambition to subject all countries to their expansionist and dominationist policy and deprive them of their rights to self-determination," KCNA reported. "The two peoples of Syria and the DPRK are as ever struggling for their rights to self-determination and national sovereignty and the security and prosperity of their countries," it added, using the initials for the country's official name, the Democratic People's Republic of Korea.

A separate message sent by Assad honored the fifth anniversary of Kim becoming North Korean leader, according to KCNA.

The positive messages have gone both ways. According to North Korean state newspaper Rodong Sinmun, Kim sent Assad a message last week to honor the 70th anniversary of the Syria's Baath Party and another this week to commemorate the anniversary of the Syrian revolution in 1963.

A close relationship between Syria and North Korea is far from new. North Korea had originally supplied military training to Syria, but the relationship later expanded to weapons sales including ballistic and chemical weapons.

North Korean military advisers and air defense troops aided Syria after the 1967 and 1973 wars with Israel. Pyongyang is later believed to have provided some of the technology used to build the secret Kibar nuclear site in Syria, which was destroyed by an Israeli airstrike in 2007.

There were unconfirmed reports that North Korean military advisers have helped Assad's forces in the Syrian civil war.

In the era of President Donald Trump, both countries are facing renewed tension with the United States. Where the new American leader had once spoken hopefully of peacefully reaching agreement with both Syria and North Korea, he now seems increasingly open to force. Last week, the U.S. military launched 59 cruise missiles at a Syrian military airfield, marking a major shift in U.S. Syria policy.

Meanwhile, Trump tweeted Tuesday that the United States will "solve the problem" of North Korea with or without the help of China.

This threat of military action seems to have forged a tighter bond between Assad and Kim, both Western-educated scions of isolated political dynasties. The media of both countries note not only their correspondence, but also their condemnation of the international pressure on them. Last month, Syria's Foreign Ministry issued a condemnation of U.S.-South Korean military exercises and reiterated Syria's "support to the people and brave leadership of Democratic Korea."

North Korea's Rodong Sinmun reported Tuesday that a spokesman for the Foreign Ministry said the U.S. military strike on Syria was an act of aggression that showed why North Korea needs nuclear weapons. "What happened in Syria once again taught a bitter lesson that no one should have an illusion about the imperialists, and one can defend oneself from the imperialist aggression only when one has one's strength," the spokesman said.