Emperor Akihito greeted Vietnamese President Truong Tan Sang with a welcoming message in a meeting Monday at the Imperial Palace, the Imperial Household Agency said.

The Emperor told the Vietnamese president and his wife, Mai Thi Hanh, who are on a four-day state visit to Japan since Sunday, "I'm delighted to welcome you on a day that heralds the arrival of spring."

Sang replied that exchanges between Vietnam and Japan have been increasing and bilateral relations have improved dramatically.

The meeting was preceded by a welcoming ceremony in a palace garden attended by the Emperor, Empress Michiko, Crown Prince Naruhito and Prime Minister Shinzo Abe and his wife, Akie.

Before departing for Japan, Sang told reporters in Hanoi on Friday that Vietnam seeks to maintain maritime and aviation safety, as well as peace and security, through cooperation with partners such as Japan and the ASEAN countries.

With China actively asserting its claims to disputed territory in Asian waters, including in both in the South China Sea and the East China Sea, security and economic cooperation between Vietnam and Japan is expected to top the agenda in his talks Tuesday with Abe.

"We follow with deep attention" the situation over the East China Sea, where Japan and China are involved in a territorial dispute, Sang said.

Vietnam hopes countries will "adequately handle existing differences" through peaceful dialogue and on the basis of "compliance with the international law," he added.

Vietnam and other members of the Association of Southeast Asian Nations are involved in disputes with China over the ownership of shoals and coral reefs in the South China Sea.

Sang suggested that care must be taken toward the needs of developing countries if the Trans-Pacific Partnership free trade talks are to reach a deal soon.