U.S. President Donald Trump has signaled a willingness to make a new deal with Iran to replace the one he unilaterally abandoned during his first term, but he has warned that failure to do so would lead to “bombing.”

In a letter to Iran on March 12, Trump proposed direct negotiations and warned of the possibility of military action if Tehran refused to engage.

In response, Iran told the United States, via Oman, that it would only agree to indirect talks over its nuclear program, ruling out direct negotiations under pressure and threats.

Two U.S. officials familiar with internal discussions at the White House told Axios that no decision has been made, but that the Trump administration is considering Iran’s offer of indirect talks.

“After the exchange of letters, we are now exploring next steps in order to begin conversations and trust building with the Iranians,” one official said.

The Pentagon on Tuesday deployed additional military assets to the Middle East and ordered another aircraft carrier to the region amid rising tensions with Iran.

On Monday, Leader of Islamic Revolution Ayatollah Seyyed Ali Khamenei dismissed Trump’s threat of military strikes, but warned of “a severe blow” if the United States or Israel launched an attack.