The United States is promising to increase pressure on Iran following an alleged foiled plot to assassinate the Saudi ambassador to Washington.

In prepared testimony Thursday, Treasury Undersecretary David Cohen said the U.S. will continue to develop what he called “new and innovative ways” to crack down on Iran and its central bank, including with possible new sanctions. In his statement to the Senate banking committee, he said such moves would “impose additional costs” on Iran and give the U.S. more leverage in dealing with Tehran.

The U.S. Justice Department Tuesday charged Manssor Arbabsiar, a naturalized U.S. citizen with an Iranian passport, and Gholam Shakuri, an Iran-based member of the Iranian Quds force, with conspiring to kill Saudi ambassador Adel al-Jubeir.

The U.S. Treasury Department has already announced economic sanctions against Arbabsiar and Shakuri, as well as three officers of Iran's Revolutionary Guard.

The United States has previously imposed sanctions on Tehran for its nuclear enrichment activities and refusal to cooperate with the United Nations' nuclear watchdog agency.

Cohen says those sanctions are already paying off.

Iran maintains its nuclear program is for peaceful purposes.