The US government, while pushing for tougher sanctions against Tehran, has given $107 billion in the last 10 years to US and foreign companies doing business in Iran, much of it in the energy sector, The New York Times reported Saturday. Despite the threat of punishment for companies that seek US federal contracts while dealing with Iran, the Times said successive administrations have struggled to exert authority over foreign companies and overseas units of US firms. Of the 74 companies the newspaper said it had identified as doing business with both the US government and Iran, 49 still work with Iran and have no announced plans to leave. “Many of those companies are enmeshed in the most vital elements of Iran's economy,” the Times said of its analysis of federal records, company reports and other documents. “More than two-thirds of the government money went to companies doing business in Iran's energy industry – a huge source of revenue for the Iranian government and a stronghold of the increasingly powerful Islamic Revolutionary Guards Corps, which oversees Tehran's nuclear and missile programs. Companies the Times said had shared the $107 billion in US contract payments, grants and other benefits between 2000 and 2009 while doing business in Iran, directly or through subsidiaries, included: l Global energy giant Royal Dutch Shell l Brazilian state energy conglomerate Petrobras l US aviation and aerospace company Honeywell l Japanese carmaker Mazda l South Korean engineering group Daelim Industrial The State Department had no immediate comment, spokesman Fred Lash said. The United States has joined Britain, France and Germany to push for a fresh set of sanctions against Iran over its nuclear program, including restrictions on new Iranian banks abroad and “vigilance” against Iran's central bank. The UN Security Council has imposed three rounds of sanctions against Iran for defying UN demands to stop nuclear enrichment. Tehran rejects Western charges that its nuclear program is designed to develop atomic weapons and says it will be used only to generate electricity. Russia and China, which both have veto power on the Security Council, have lucrative trade ties to Tehran but Moscow has signaled it could support new punitive steps against Iran as long as they were not too severe. China has not ruled out supporting new sanctions but has said repeatedly the issue should be settled through dialogue. The Iran Sanctions Act of 1996 gives the US president a range of actions to use against companies but Congress is considering tougher steps mandating that firms investing in Iran's energy sector be denied federal contracts. “We need to send a strong message to corporations that we're not going to continue to allow them to economically enable the Iranian government to continue to do what they have been doing,” Representative Ron Klein, who wrote the contracting legislation, told the Times. The paper said the Obama administration points to decisions by a number of companies to pull out of Iran or hold off on new investment as a sign Washington has been successful at pressing governments and executives to curtail investment in Iran. “We are very aggressive, using a range of tools,” Denis McDonough, chief of staff to the National Security Council, told the Times.