WASHINGTON (Reuters) - The US Treasury Department announced new measures on Tuesday aimed at choking finances for Iran's military and for a shipping line that Treasury says engages in illegal activity. Treasury said it was targeting financial networks that support the Islamic Revolutionary Guard Corps (IRGC) and its national carrier, the Islamic Republic of Iran Shipping Lines (IRISL)."Both the IRGC and IRISL are major institutional participants in Iran's illegal conduct and in its attempts to evade sanctions," said Stuart Levey, Treasury's under secretary for terrorism and financial intelligence. IRISL was originally designated by Treasury in 2008 for alleged involvement in illicit arms shipments. Levey said it was primarily involved in container shipments and was not a bulk carrier for movement of Iranian oil products. Treasury said the shipping line uses a variety of deceptive behavior to try to mask its activities including falsifying shipping documents, changing nominal ownership of its ships and repainting them to hide the fact that they are part of IRISL. Levey said Tuesday's actions were intended to restrict financing for the guard corps and shipping line rather than to affect oil trade. Treasury named two Iranian banks -- Ansar Bank and Mehr Bank -- as supporters of the IRGC and said it was banning them from any participation in US financial and commercial systems and prohibiting US citizens from any dealing with them. It also designated a cooperative called Bonyad Taavon Sepah that Treasury said was formed by IRGC commanders to handle its investments. Bonyads are quasi-official organizations that get benefits from the Iranian government and handle a significant part of the country's non-petroleum economy, Treasury said. "The IRGC continues to be a primary focus of US and international sanctions against Iran because of the central role it plays in Iran's missile and nuclear programs, its support for terrorism, as well as its involvement in serious human rights abuses," Treasury said. With the IRGC's expanding influence and control over broader segments of the Iranian economy, including defense production, construction, and oil and gas industries, increasing numbers of Iranian businesses are subsumed under the IRGC's umbrella and identified with its illicit conduct. Levey said the United States intends to keep up pressure on Iran. "It's clear that it's important for us to continue to impose pressure...to highlight the fact that firms are looking for ways to help Iran evade international sanctions," he said.