Japanese stocks recorded their steepest drop since April as rising oil prices and escalating tensions in the Middle East weighed heavily on the country’s economic outlook.

Japan and the United States are exploring the addition of a nuclear power project to the second round of deals under Japan’s $550 billion investment package. The project is expected to involve Westinghouse and aims to strengthen both countries’ energy supply chains amid rising Middle East tensions.

Tokyo stocks ended lower on Wednesday, with the benchmark Nikkei index posting its fifth consecutive decline amid concerns over escalating trade tensions between the U.S. and Europe regarding Greenland.