The Bush administration issued a fresh warning Thursday to U.S. banks that Iran is using "an array of deceptive practices" to hide its alleged involvement in nuclear proliferation and terrorist activities.

The Treasury Department's Financial Crimes Enforcement Network alleged that Iran is resorting to such alleged practices to evade detection and skirt financial sanctions.

"The government of Iran disguises its involvement in proliferation and terrorism activities through an array of deceptive practices specifically designed to evade detection," FinCen said in its warning to banks.

For instance, the agency said that the Iran's central bank, also known as Bank Markazi, and Iranian commercial banks have requested that their names be removed from global financial transactions to make it difficult to "determine the true parties in the transaction."

It marked the government's latest effort to ramp up pressure on Iran, which the United States accuses of bankrolling terrorism and seeking a nuclear bomb.

The United States' warning to U.S. banks comes after an international financial watchdog _ the Paris-based Financial Action Task Force _ pressed its 34 member countries to urge banks to monitor their dealings in Iran. The watchdog group said Iran hasn't done enough to fight money laundering and to combat terror financing.

In Thursday's warning, the U.S. government told U.S. banks that the Treasury Department is "particularly concerned that the central bank of Iran may be facilitating transactions for sanctioned Iranian banks."

Under U.S. financial sanctions, virtually all trade and investment activities with the government of Iran _ including government-owned banks _ are prohibited. Moreover, other sanctions have been imposed on Iranian entities that the United States believes are linked to terrorist activities and the spreading of weapons of mass destruction.

The State Department, meanwhile, said vessels that arrived at U.S. ports after recent visits to Iran "will be scrutinized" because Iran has not maintained effective anti-terrorism measures in its ports.

The U.N. Security Council recently passed a third round of sanctions on Iran ordering financial assets to be frozen of additional Iranian officials and companies with links to the country's nuclear and missile program. For the first time, it also banned trade with Iran in some goods that have both civilian and military use.

Iran insists its enrichment program is intended to produce fuel for nuclear reactors that would generate electricity and has vowed to push ahead with it.