South Korea's foreign ministry has been fine-tuning schedules to have bilateral ministerial talks with more than a dozen countries, including the United States, on the sidelines of an upcoming regional security forum, ministry sources said Thursday.

Foreign Minister Kang Kyung-wha will attend ASEAN-related meetings that will kick off in Manila, the Philippines, on Aug. 6.

They include the ASEAN Regional Forum to be held on Aug. 7.

The ARF is known to be a rare event joined by North Korea, along with the other five countries involved in the suspended six-party denuclearization talks on Pyongyang's nuclear program.

South Korea, the US, Japan, China and Russia usually send their top diplomats to the gathering every year.

"There are more than a dozen countries that we are currently discussing holding bilateral ministerial meetings with," a foreign ministry official said on condition of anonymity. "We are working on holding a meeting with the US as well."

He said that the number could grow further.

Kang held her first face-to-face talks with US Secretary of State Rex Tillerson in Washington in late June, just ahead of a summit between their leaders.

Their potential second meeting would come amid increased tensions on the Korean Peninsula following the North's claim on July 4 that it successfully test-fired an intercontinental ballistic missile.

Despite the latest provocation, the Seoul government recently made an offer to hold inter-Korean talks to ease tensions and resume reunions of families separated by the 1950-53 Korean War.

The North has stayed mum on the overtures.

North Korea will also likely join the ARF with its Foreign Minister Ri Yong-ho expected to lead its delegation. Expectations are growing of an encounter between Kang and Ri, as the Seoul government has not ruled out the possibility, nor has it confirmed any such plan.

"The government's stance is to make steady efforts to create an environment for the resumption of denuclearization talks by using diverse channels... while at the same time taking stern action against the North's provocations," Cho June-hyuck, ministry spokesman, said at a regular press briefing.

"At this moment, we do not have any detailed plan to hold foreign ministers' talks between the two Koreas," he added.

A high-ranking ministry official also expressed caution against inter-Korean talks in the Philippines, saying that it would happen "when conditions permit."

On the sidelines of the ARF held in Laos last year, then Foreign Minister Yun Byung-se and Ri exchanged just a brief greeting in an unexpected encounter.

Meanwhile, citing an anonymous diplomatic source, a Japanese newspaper earlier reported that the US has been asking 27 ARF member states to prevent the North from joining the annual forum.

Ministry officials close to the matter here have not commented on the report. (Yonhap)