WASHINGTON (JTA) – Three US lawmakers urged the Obama administration to take action against two ship registry companies that they claim have violated Iran sanctions.

Sens. Mark Kirk (R-Ill.) and Robert Menendez (D-N.J.) sent a letter Tuesday to President Obama asking him to designate the United Arab Emirates-based Tanzania Zanzibar International Register of Shipping and the Singapore-based Tuvalu Ship Registry as having violated the Iran Threat Reduction and Syria Human Rights Act. The lawmakers say the companies are illegally helping to send goods to Iran.

Rep. Howard Berman (D-Calif.) called on the Obama administration to take action against Tuvalu, a small South Pacific Island, for reflagging Iranian oil tankers. He said the nation has reflagged 22 Iranian oil tankers, despite warnings that it could face US sanctions.

The owners of a ship are masked when it carries a new flag, so it is easier for Iran to obtain insurance and financing for cargoes as well as to find buyers without catching the eye of the United States and European Union.

Under the act, the president must take action against any non-US firm transacting with Iran in the areas of energy, insurance and shipping. The US sanctions have curbed Iranian oil imports by most other major nations.

“Within the last several months, the ship registries of Tanzania and Tuvalu reflagged as many as 33 oil tankers owned or controlled by NITC,” the National Iranian Tanker Company, the senators said in their letter.

Another 25 vessels under a Tanzanian registry were reflagged, according to the letter.

Berman’s letter, sent to Secretary of State Hillary Clinton and Treasury Secretary Timothy Geithner, recommended that they “take aggressive action to change Tuvalu’s policy of abetting Iran in evading US sanctions.”

In response, Tuvalu confirmed it had registered NITC vessels, but said it would monitor them and take action if any vessel violated United Nations sanctions.