Japan's Prime Minister Shinzo Abe has cut short his first foreign visit since taking office to focus on the Algerian hostage crisis, where some of the victims are Japanese.
Abe, who was in Indonesia as part of a Southeast Asia tour, headed home immediately after talks and news conference with Indonesian President Susilo Bambang Yudhoyono on Friday.
The two leaders condemned the kidnapping and agreed to cooperate on fighting terrorism.
"It is totally unacceptable that such a contemptible act has caused many victims. We condemn the kidnapping and we completely agreed on that," Abe said. He called the kidnapping "an act of terrorism that claimed the lives of many innocent people and should not be tolerated."
Abe has called the Algerian leader to demand his country protect the hostages' lives.
The employer of the Japanese hostages, JGC Corp., confirmed late Friday that four more its workers were alive, in addition to the three it had earlier said were alive. But 10 others are still unaccounted for.
Algerian special forces stormed a gas plant in eastern Algeria on Thursday to wipe out Islamist militants and free hostages from at least 10 countries. The fate of the fighters and many of the captives remains uncertain.
Abe and Yudhoyono also agreed to strengthen strategic partnership in politics, security and economy. While welcoming China's economic rise as a benefit to Japan, Abe urged China to act responsibly in the region, where its growing territorial claims have caused friction. Abe stressed his hopes to deepen relations with ASEAN to contribute to the regional stability.
Abe earlier visited Vietnam and Thailand, making Southeast Asia the destination of his first foreign visit since taking office in December, signaling the importance of the region to his foreign policy.
Abe said he hoped to deepen ties with ASEAN nations amid China's growing maritime activity. Japan and China are in a political battle over a group of tiny East China Sea islands, and Beijing has separate territorial disputes with several Southeast Asian countries.
"Open seas are public assets and Japan will do utmost to protect them by cooperating with ASEAN," Abe said in introducing his main diplomatic policy for the region.
"China's economic rise is definitely a plus for Japan but it is important for China to act responsibly as part of international society," Abe told the news conference. "Japan hopes to contribute to regional stability and development while strengthening our relations with neighbors such as ASEAN. That is Japan's national interest."
Abe also promised to develop business networks across the region to promote trade and investment to revive Japan's economy and help ASEAN countries.
Yamaguchi reported from Tokyo.