SEOUL, South Korea — South Korean police were on high alert in Seoul on Tuesday to monitor protests by both critics and supporters of President Donald Trump as the U.S. leader arrived in the country amid concerns over North Korea’s nuclear threats.

Under the close watch of police, dozens of anti-Trump protesters rallied near the presidential office, holding signs that read “Trump, NOT welcomed!” and “Say no to Trump, say no to war.”

The demonstrators accused the outspoken president of raising animosity with North Korea and pressuring Seoul to buy more U.S. weapons. They also accused him of pressing Seoul to re-do a bilateral free trade deal between the countries so that it’s more favorable to the United States.

“We oppose the visit to South Korea by Trump, who has heightened the fears of war on the Korean Peninsula,” said one of the protesters, reading off a released statement. The group, which calls itself the “No Trump Coalition,” also plans to protest on Wednesday near Seoul’s parliament, where Trump plans to make a speech calling on the international community to maximize pressure on North Korea.

Trump’s supporters, many of them conservative older South Koreans, were also planning rallies in nearby streets, reflecting a public deeply divided along ideological and generational lines.

More than 15,000 officers will be deployed to provide security during Trump’s visit and monitor the demonstrations, according to the National Police Agency. Scores of officers in fluorescent green jackets were seen patrolling near the presidential office and U.S. Embassy, while hundreds of buses were used to create tight perimeters in nearby streets.

Officers installed steel fences at a large boulevard across the embassy where a protest zone was set. Police had unsuccessfully attempted to block anti-Trump protesters from marching in streets near the presidential palace, with the Seoul Administrative Court ruling that such a ban would infringe on the protesters’ freedom of assembly.

Pro- and anti-Trump protesters have been staging dueling but peaceful protests in Seoul in recent weeks ahead of Trump’s visit. Many South Koreans are concerned that Trump’s fiery rhetoric on North Korea, which has included threats of military options, is raising the risk of an unwanted war on the Korean Peninsula that could cost thousands of South Korean lives.

Others, including older people who tend to be more conservative, are supportive of Trump’s tough stance against the North, which has been accelerating its nuclear weapons and missile tests in recent months, and accuse liberal South Korean President Moon Jae-in of being too soft on Pyongyang.

The conservative Korea Freedom Federation released a statement welcoming Trump’s visit, which it described as a “God-like move” that would “instantly reverse” the security situation on the peninsula after the allies had been forced to the “defensive” by North Korea’s weapons tests. However, the group also lamented Trump’s decision not to visit the heavily guarded demilitarized zone between the Koreas during his visit to the South, saying that it might lead North Korea to misjudge that its provocations have hurt the allies’ morale.

Meanwhile, in the Philippines, dozens of protesters burned a portrait of Trump in downtown Manila on Tuesday, saying the president, who will join a summit of East Asian leaders next week in the country, is not welcome there. Members of Kadamay, an alliance of urban poor activists, camped out at a bridge near the presidential palace and chanted “Ban Trump in the Philippines!”