North Korea's provocations will only strengthen South Korea's trilateral cooperation with the United States and Japan, President Yoon Suk Yeol said Monday, urging full-fledged preparations against any military threats from the North.

Speaking at the Cabinet meeting on the first day of 11-day joint exercises with the US, Yoon touted the three-way partnership on security and economy as a "solid structure" that would lower the risk of North Korea's provocations and transform the growing global challenges into new opportunities.

"As North Korea's provocative threats increase, the foundation of trilateral security cooperation among South Korea, the US and Japan will grow even stronger," Yoon said.

"Economic cooperation and enhanced human exchanges among the three countries (will) contribute (to) South Korea's efforts in securing future growth engines and quality high-income jobs."

The trilateral partnership that was formalized at a Camp David summit in the US on Friday will also further develop as a platform contributing to regional security, along with the AUKUS pact between the US, Britain and Australia, and the Quad, which consists of the US, Japan, India and Australia, Yoon added.

The president also explained that this year's Korea-US joint drills have been upgraded to include integrated civil, government and military coordination to deter evolving nuclear threats from the North.

“North Korea will use all available means to achieve its war objectives, even nuclear weapons,” Yoon said. “Starting from this year’s exercise, we will conduct the first government-level drill to respond to North Korea’s nuclear program.”

On Monday, the two allies initiated 11 days of comprehensive joint military exercises, known as Ulchi Freedom Shield. South Korea also held separate four-day pan-governmental training exercises involving more than 500,000 participants in preparation for a national emergency, and civil defense training for the public will be held nationwide on Wednesday as part of the Ulchi Exercise.

The current government has “normalized” the Ulchi Exercise, which had been scaled down under the previous government, Yoon said, referring to the former left-wing Moon Jae-in administration.

Yoon urged officials to publicize the nuclear warning dissemination system and guidelines for public action, and to check the national response capability for public relief and treatment.

Yoon told the Cabinet to be wary of fake news spread by the North. "From the beginning of the war, North Korea will cause extreme social confusion and division through the spread of fake news and propaganda instigation using anti-state forces," he said. This can "hinder" quick wartime transitions and "lead to a loss" even before full-scale fighting.

"Next, North Korea will try to paralyze the national infrastructure by attacking important national facilities," he said. "If nuclear power plants, high-tech industrial facilities and the national communication network are destroyed by missiles, drones or cyberattacks, our ability to sustain war and the lives of the people will be greatly hindered," he said, calling for "drastic" improvements in protection measures for important national facilities.

Meanwhile, the Defense Ministry said this year's UFS will be divided into two parts. The first part, in conjunction with government practice, will be held from Monday to Friday, while the second part, conducted solely by the military, will take place from Aug. 28-31.

The armies, navies, air forces, marines and space forces of both South Korea and the US are participating in the drills. In addition, United Nations member countries such as Australia, Canada, France, Britain, Greece, Italy, New Zealand, the Philippines and Thailand will also join.

South Korea and the US are reported to have completely reorganized the scenario, which in the past proceeded in the order of "local provocation in North Korea" followed by "carrying out an all-out war." The scenario now reflects advanced North Korean nuclear and missile capabilities and intentions, the potential spread of fake news in the case of war and lessons learned from the ongoing conflict in Ukraine.

As part of the Ulchi Exercise, civil defense training will be held at 2 p.m. on Wednesday. In Seoul, 20 minutes of training will be conducted to prepare for air raids across the capital city. A 15-minute air-raid warning will be followed by a five-minute alert. When an air raid warning is issued, people must move quickly to civil defense shelters.

Yoon also said the outcome of a trilateral summit held at Camp David in the US last week will decrease risks and increase opportunities for South Korea.

He said the summit institutionalized and solidified the comprehensive cooperation system among the three countries. Referring to the results of the annual meeting of the three nations, he said the summit will evolve into a pan-regional cooperative effort that contributes to building freedom, peace and prosperity throughout the entire Indo-Pacific region.

Amid momentum building over the potential of the trilateral partnership, Yoon's approval rating fell to the mid-30 percent range, a poll showed Monday.

Realmeter's four-day evaluation of Yoon's performance in state affairs, conducted Aug. 14-16 at the request of the Media Tribune, was 35.6 percent, down 2.7 percentage points from the previous week.

The decline is largely attributed to the aftermath of the chaos at the Saemangeum World Scout Jamboree, while the results of the South Korea-US-Japan summit were not yet reflected during the survey period, according to the pollster.