"We should not give in to emotions and push Pyongyang into a corner," Putin said in a news conference after the meeting, held on the sidelines of a conference on economic development of Russia's Far East. "As never before, everyone should show restraint and refrain from steps leading to escalation and tensions."

Moon said the leaders agreed that reducing regional tension and "quickly solving" the security challenges posed by North Korea's nuclear and missile program were critical. Ahead of his meeting with Putin, Moon said the situation could get out of hand if North Korea's missile and nuclear tests aren't stopped.

Moon urged Russia to back stronger sanctions including the cutting off oil supplies, but Putin expressed concern that such moves would hurt regular North Koreans, said Yoon Young-chan, Moon's chief press secretary.

"Myself and President Putin share a view that North Korea has gone the wrong way with its nuclear and missile program and that easing tension on the Korean Peninsula is an urgent issue," Moon said during the news conference.

Moon, in a phone call with Putin before the conference, also called for a ban on overseas North Korean workers, who are a key foreign currency source for the North. Putin told Moon that the North Korean problem should be solved diplomatically, according to Seoul's presidential office.

Moon took office in May calling for a diplomatic focus, but the torrid pace of North Korea's weapons tests had hardened his government's stance.

Japanese Prime Minister Shinzo Abe, who will meet Putin in Vladivostok on Thursday, said before his departure from Japan that "we must make North Korea understand there is no bright future for the country if it pursues the current path."

The US military is starting to add more launchers to a contentious US missile-defense system in South Korea to better cope with North Korean threats. The deployment of the Terminal High-Altitude Area Defense system has angered North Korea but also China and Russia, which see the system's powerful radar as a threat to their own security.

A THAAD battery normally consists of six launchers that can fire up to 48 interceptor missiles, but only two launchers have been operational so far at the site in rural Seongju.

Several US military vehicles, including trucks carrying payloads covered in black sheets that appeared to be launchers, were seen heading toward a former golf course where the system has been installed.

Dozens were injured earlier as police sent thousands of officers to remove hundreds of protesters from a narrow road leading to the site.

Seongju residents and activists have raised worries over rumored health hazards and the possibility of being targeted by North Korean attacks. (AP)