U.S. Secretary of State John Kerry arrived in Japan on Sunday for the last stop of his Asian tour, a trip that has largely focused on the provocations coming out of North Korea.

He spent early Sunday visiting a 620-year-old Buddhist temple and spoke with university students on their views on America and global issues. He is scheduled to meet with Japanese Foreign Minister Fumio Kishida later in the day.

His visit comes amid heightened regional tensions.
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North Korea issued a scathing warning to Japan on Friday, saying Tokyo should "stop recklessly working for staging a comeback on Korea, depending on its American master," state media reported.

Japanese foreign minister spokesman Masaru Sato said such remarks only hurt North Korea.

"Japan would not be pushed around by rhetoric of North Korea," he said.

Japan's Transport Ministry has issued a notice requiring its airplanes to report to the U.S. military if they fly near the U.S. military's Kadena base in Okinawa prefecture, the Kyodo News Agency said.

The notice, made at the request of the U.S. military in Japan, is believed to be part of precautions taken against possible North Korean missile launches.

As Kerry visited the Japanese capital, North Korea responded to South Korea's call last week for open talks.

"If they have true intent for dialogue, they should drop the attitude of confrontation to begin with, not getting inveigled in wordplay," North Korea's state-run media KCNA reported. "The possibility of dialogue entirely depends on their attitude."

South Korean Foreign Minister Yun Byung-se, speaking with Kerry on Friday, urged North Korea to open talks.

"We urge North Korea to cease its reckless behavior and to stop issuing threats," he said.

In his first trip to Asia as secretary of state, Kerry visited South Korean and Chinese leaders as tensions stemming from North Korea loomed.

On Saturday, Kerry and Chinese leaders said their two nations would work together to press North Korea to tone down its provocations.

Kerry told reporters in Beijing that the United States and China are calling on North Korea to refrain from any provocative steps -- including any missile launches.

But, he said, both nations want to focus on a peaceful solution, not "threat-for-threat or confrontational language. There's been enough of that."

No option was left off the table in his talks with Chinese leaders, he said. Among those he met Saturday were Chinese President Xi Jinping and Premier Li Keqiang.