SEOUL - A top US diplomat expressed regret on Sunday over a US immigration raid that detained hundreds of South Korean workers, proposing making the event a turning point to strengthen bilateral relations, South Korea said.

In a meeting in Seoul, First Vice-Foreign Minister Park Yoon-joo urged Deputy Secretary of State Christopher Landau to push forward bilateral discussions on follow-up measures, including a new visa category, the foreign ministry said in a statement.

Some 300 South Korean workers returned home to cheers and emotional reunions on Friday, a week after being detained in the massive immigration raid at a Hyundai Motor battery plant in Georgia - an event that sent shockwaves across South Korea.

To prevent the recurrence of such an incident, Seoul has called on the US to provide clear guidelines for existing business visas and create a new visa category for Korean professionals to support massive investment projects by Korean businesses in the US.

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In Sunday's meeting, Landau called for Washington and Seoul to speed up working-level consultations to ensure the issuance of visas commensurate with the contributions of Korean workers, noting that Korean investments help rebuild manufacturing in the US, the ministry said.

The US Embassy in Seoul could not immediately be reached for comment.

Park called Landau's visit "timely" in the wake of the raid, the ministry said, quoting Landau as mentioning President Donald Trump's decision that the Korean workers would not face any disadvantages when they re-enter the US.