President Donald Trump has announced new sanctions on Iran, following increasing tensions since the weekend.

What's the background?

In late July 2018, President Donald Trump announced that he would be willing to meet with Iranian President Hassan Rouhani "without preconditions." He reportedly also said something similar in early September, and seemed to confirm as much when a reporter asked him about it and he responded with a cryptic "we'll see what happens."

On Sunday, White House adviser Kellyanne Conway said that a meeting between Trump and Iranian leaders was still on the table, and that Trump would make a statement on that soon.

Also on Sunday, however, Trump indicated that he was "locked and loaded" to respond on behalf of Saudi Arabia after a Saudi oil field was attacked. Iran has denied that it was behind the attack, but the Saudi government and some U.S. officials have blamed Iran.

On Tuesday, Iranian Supreme Leader Ayatollah Ali Khamenei said in a statement that Iran would "never talk to American officials" because this would convince the American government that its sanctions were working.

What did Trump say?

On Wednesday, Trump announced that the U.S. would be hitting Iran with financial penalties.

"I have just instructed the Secretary of the Treasury to substantially increase Sanctions on the country of Iran!" he said in a tweet.

So far, the U.S. Treasury Department has not indicated what these sanctions are or how severe they might be. The Trump administration has already reinstated all the sanctions that had been lifted under former President Barack Obama's Joint Comprehensive Plan of action, more commonly known as the Iran nuclear deal.

Spokespeople at the Treasury Department, State Department, and the White House did not respond to CNN's requests for comment.