WASHINGTON -- North Korea on Saturday welcomed what it said was a letter from U.S. President Donald Trump to North Korean leader Kim Jong Un, saying it was a sign of “the special and very firm personal relations” between the two leaders despite recent frictions.

A senior Trump administration official confirmed Trump sent the letter and said it was “consistent with his efforts to engage global leaders during the ongoing pandemic.”

The president looks forward to continued communications with Chairman Kim, the official said.

Since Trump held a third summit with Kim last June and briefly stepped into North Korea from the demilitarized zone with South Korea, no progress has been made on the U.S. president’s bid to get Pyongyang to give up its nuclear and missile programs.

North Korea has attempted a series of missile launches, including the launch of two apparent short-range missiles in the last day or so, as it tries to pressure the United States and its allies to lift economic sanctions.

North Korea state media KCNA said Kim had received a letter from Trump in which the U.S. president said he was impressed by the North Korean leader’s efforts to defend his people from the coronavirus.

Trump “expressed his intent to render cooperation in the anti-epidemic work, saying that he was impressed by the efforts made by the Chairman to defend his people from the serious threat of the epidemic,” KCNA reported in a statement carried by Kim’s sister, Kim Yo Jong. It did not say when the letter was received.

The letter said that despite good personal relations between the leaders, “if impartiality and balance are not provided and unilateral and greedy intention is not taken away, the bilateral relations will continue to aggravate.”

The report came after North Korea’s missile test on Saturday , which prompted South Korea to urge an immediate halt of “inappropriate action” in the face of the global pandemic.

In a separate dispatch on Sunday, KCNA said it was a test of a new tactical guided weapon, overseen by Kim Jong Un.

The test “clearly proved the characters of different flight trajectories and falling angles, accuracy of guided shells and their power”, KCNA said.