Environment and energy ministers from the Group of 20 economies gathered in this resort town on Saturday to find innovative ways to combat emissions-driven climate change and eliminate plastic waste. But Thursday's attacks on two tankers near the Strait of Hormuz, including one operated by a Japanese company, also raised fears among the delegates about energy security.

"Japan is paying close attention to the situation with great concern," Minister for Economy, Trade, and Industry Hiroshige Seko told the G20 delegates Saturday afternoon.

"It is vital for the international community to respond collaboratively to such incidents from the perspective of ensuring global energy security," he added.