Pentagon suspends efforts to retrieve remains of US troops from North Korea

North Korean officials haven't communicated since the Hanoi summit in February,

"We have reached the point where we can no longer effectively plan, coordinate, and conduct field operations in [North Korea] during this fiscal year, which ends on September 30, 2019," said DPAA spokesperson Lt. Col. Kenneth Hoffman. "We are assessing possible next steps in resuming communications with [North Korea] to plan for potential joint recovery operations to be scheduled during Fiscal Year 2020."

North Korea transferred 55 boxes of remains after Trump and Kim's first summit in July 2018. So far, four individuals have been identified from those remains.

DPAA estimates that over 7,600 U.S. personnel still remain unaccounted for from the Korean War.

The suspension of transfers marks another step back in U.S. and North Korean diplomacy. Trump touted the transfer of remains as one of the major successes to come out of his talks with Kim, along with the suspension of missile testing. But last month, North Korea conducted a ground weapons test followed by the launch of short range projectiles into the Sea of Japan just last week.

Pyongyang has yet to follow through with any concrete, verifiable steps to dismantle its nuclear program, despite a vague agreement between the two nations that they would commit to denuclearization.

Still, Trump continues to express optimism that he can strike a deal with Kim on denuclearization. After the regime launched projectiles on Friday, the president tweeted that Kim "fully realizes the great economic potential of North Korea, & will do nothing to interfere or end it."

ABC News' Ben Gittleson contributed to this report.