South Korea's defense ministry dismissed concerns Monday that some border security-related information might have been leaked to North Korea as its top officials were allowed to use a strategically important road to visit here.

Kim Yong-chol, vice chairman of the North's Party Central Committee in charge of inter-Korean relations, and his entourage were supposed to pass through the Tongil Bridge in Paju, north of Seoul, on Sunday.

But their motorcade took an alternative route via the Jeonjin Bridge, a military infrastructure about 10 kilometers east of the Tongil Bridge, to avoid protesters who were blocking the road at that time.

Lawmakers with the main opposition Liberty Korea Party and conservative activists were fiercely opposed to Kim's trip to the South, whose main purpose was for him to attend the closing ceremony of the PyeongChang Winter Olympics.

In particular, they cited reports that Kim led the North's 2010 torpedo attack on South Korea's Cheonan corvette that killed 46 sailors, while also serving as the country's intelligence and anti-South Korea operation chief.

Asked about the decision to let him cross the border on Route 372 over the Jeonjin Bridge, the Ministry of National Defense said it was made in accordance with "consultations among relevant authorities."

"It does not appear that such military information was exposed (to the delegation) given the speed of their vehicles and routes," the ministry's spokesperson Choi Hyun-soo said at a press briefing.

She was responding to criticism that the North Koreans might have been given a chance to catch a glimpse of a number of military operation zones and facilities, especially by crossing the Imjin River over the bridge built in 1984 by the military and local administrative authorities.

The bridge is situated just south of the demilitarized zone in a region defended by the South Korean Army's First Division. Local residents sometimes use the bridge, and it's also open to civilians who receive prior approval.

Route 372 is an ordinary road, not a military or tactical one, the ministry added.

In the meantime, close to 300 North Korean athletes, supporters and reporters returned home on Monday via the Tongil Bridge, which serves as the gateway for most overland inter-Korean trips. The PyeongChang Games finished the previous day.

Keen attention is being paid to the schedule for the annual combined military drills of South Korea and the United States.

The allies postponed the Key Resolve and Foal Eagle exercises until after the end of the PyeongChang Paralympics on April 18.

The North has long called for a halt to the training, arguing it brings the peninsula to the brink of another war.

Conservatives here are worried that the liberal Moon Jae-in administration may seek to scale down or suspend the exercises in a bid to maintain the momentum of Olympics-driven rapprochement with the North.

"There's no review (of our position) on North Korea's demand," Army Col. Roh Jae-cheon, spokesman for the Joint Chiefs of Staff, told reporters. "We will push for the drills as planned." (Yonhap)