SEOUL (REUTERS) - South Korea's top diplomat plans to visit Washington next week, officials said on Thursday, as Seoul pledged a solid alliance with the United States regardless of the presidential election results.

Democratic challenger Joe Biden predicted victory on Wednesday Nov 4) after winning two key US states, while President Donald Trump alleged fraud, filed lawsuits and demanded recounts in a race yet to be decided a day after polls closed.

South Korea's foreign minister Kang Kyung-wha will arrive in Washington on Sunday for a four day stay, the ministry said.

The trip came at the invitation from Secretary of State Mike Pompeo who cancelled his planned visit to Seoul last month after Trump tested positive for the coronavirus.

The ministers will hold a meeting over bilateral and regional issues including stalled talks aimed at dismantling North Korea's nuclear and missile programmes in exchange for US sanctions relief.

Despite uncertainty over the US election, South Korea's presidential Blue House said it would maintain the "solid"alliance whoever wins the White House.

"Regardless of the election outcome, our government will not only maintain the solid alliance with the United States but also continue cooperation to develop it further," Blue House spokesman Kang Min-seok told a briefing.

"We will also actively cooperate with a new administration to achieve the goal of denuclearising the Korean peninsula and building a peace regime, and closely communicate in line with the traditions that the two countries have worked together with any governments from each other."

The Blue House was cautiously monitoring the US election, with President Moon Jae-in scheduled for no public activity on Thursday.

The presidential National Security Council was set to gather at 3pm to discuss developments, Kang said.