SEOUL, KOREA, REPUBLIC OF -- South Korea's leader said Monday he'll use his upcoming summit with U.S. President Joe Biden to push to restart diplomacy with North Korea, saying that the U.S. has opted for a diplomatic, phased approach to resolve the North Korean nuclear crisis.

The White House recently said officials completed a review of North Korea policy and suggested the Biden administration would seek a middle ground between Donald Trump's "grand bargain" and Barack Obama's "strategic patience" approaches as a way to curb the North's nuclear ambitions.

In a nationally televised news conference, President Moon Jae-in said he welcomes the direction of the Biden administration's North Korea policy, which he said was finalized after consultations with South Korea. Moon said Biden's North Korea policy aims to achieve "the Korean Peninsula's complete denuclearization through diplomacy with a flexible, gradual and practical approach."

The Biden administration hasn't disclosed details of its North Korea policy review. But administration officials have signalled they are trying to set the stage for incremental progress, in which denuclearization steps by the North would be met with corresponding actions, including sanctions relief, rather than a Trump-style push for an immediate, comprehensive deal through a leader-to-leader summit.

Some experts oppose a step-by-step denuclearization process because North Korea could derail negotiations while keeping much of its nuclear arsenal, after some of the most crippling international sanctions are lifted.

Moon said when he meets Biden for their first summit talks in Washington on May 21, he'll try to bolster the bilateral military alliance, boost policy co-ordination on North Korea and find ways to resume stalled talks between Washington and Pyongyang and between Seoul and Pyongyang.

Moon, whose single five-year term is to end next May, said he'll focus on establishing lasting peace on the Korean Peninsula during his final year in office.

"I will not be pressed by time or become impatient during the remainder of my term. However, if there is an opportunity to restart the clock of peace and advance the peace process on the Korean Peninsula, I will do everything I can," Moon said. "I look forward to North Korea responding positively."

Moon, who champions a greater reconciliation with North Korea, once shuttled between Pyongyang and Washington to facilitate the now-dormant nuclear diplomacy between North Korean leader Kim Jong Un and Trump. Inter-Korean exchanges and co-operation programs also flourished.

But the Kim-Trump diplomacy eventually fell apart during their second summit in Vietnam in early 2019 due to wrangling over U.S.-led sanctions on North Korea. Pyongyang later suspended communications with Seoul and halted all major joint co-operation programs.

Kim's government hasn't made an official response to the Biden administration's North Korea policy review. But his Foreign Ministry last week warned Washington of "a very grave situation" while criticizing Biden for calling North Korea's nuclear program a serious security threat in his address to Congress.

Moon said he doesn't believe North Korea is rejecting talks with the Biden administration. He said North Korea will likely soon have a final review on its policy on the new U.S. government.

In January, Kim said the fate of ties between North Korea and the United States would depend on whether Washington would abandon what it considers a hostile policy on Pyongyang. North Korea has long wanted the United States to lift sanctions on it and provide a security guarantee.