Executives of a Tokyo-based engineering equipment manufacturer under arrest on suspicion of illegally exporting grinding machines to Iran were fully aware exporting the jet mills was illegal, investigative sources alleged Friday.

According to the sources, the five executives, including Haruhiko Ueda, 68, president of Seishin Enterprise Co., offered Iranian firms data showing the machines could be used in the manufacture of solid fuel for missiles. Police said earlier Ueda admitted exporting the mills to Iran but denied violating any laws.

The Metropolitan Police Department arrested Ueda and four managers of the firm for allegedly violating the Foreign Exchange and Foreign Trade Control Law by exporting the machines without permission.