Iran will never succumb to U.S. pressure, and if Washington wants talks with Tehran it should show respect, Foreign Minister Mohammad Javad Zarif said on Monday.

Tensions between Tehran and Washington have risen sharply in recent weeks, a year after Washington exited a 2015 deal between Iran and world powers that curbed Tehran's nuclear program in exchange for lifting international financial sanctions.

"Iran will never yield to pressure from the United States, " Zarif said in a speech broadcast live on state TV. 

"America should try to respect Iran," he said, adding, "if they want to talk to Iran, they should show respect."

Trump has called for talks with Iran's clerical rulers with "no preconditions. " Tehran has ruled this out, saying Trump should return to the deal if he wants to negotiate with Iran.

In an unprecedented step to up pressure on Iran after Tehran's downing of an unmanned American drone last month, Trump imposed sanctions on Iran's top authority Supreme Leader Ayatollah Ali Khamenei and other senior Iranian officials.

Iranian President Hassan Rouhani said last week sanctions against Khamenei would fail because he had no assets abroad. Rouhani described the latest round of sanctions as a sign of U.S. desperation.

"The White House actions mean it is mentally retarded," he said. "Tehran's strategic patience does not mean we have fear."

"Imposing useless sanctions on Khamenei and other officials is the permanent closure of the path of diplomacy," Abbas Mousavi, Iranian Foreign Ministry spokesman, said in a tweet.

"Iran has no interest to increase tension in the region and it never seeks war with any country, including [the] U.S.," Rouhani said by phone to his French counterpart Emmanuel Macron.

"We have always been committed to regional peace and stability and will make efforts in this respect," Rouhani told Macron.

Acting U.S. Defense Secretary of the United States Mark Esper told NATO allies last Thursday that Washington did not want to go to war with Iran but also could not tolerate any further incidents, according to allied diplomats present.

"Our goal is to bring Iran to the negotiating table to conclude a comprehensive, enduring deal that addresses Iran's nuclear program, its ballistic missile development and proliferation, its support for terrorism and other malign activities," Esper said.

"Again, we do not seek armed conflict with Iran, but we are ready to defend U.S. forces and interests in the region," he added.

(With input from Reuters)