American detained in Iran ends 7-day hunger strike, calling it 'weapon of last resort'

Siamak Namazi, a U.S. citizen who has been detained in Iran since 2015, has ended his seven-day hunger strike, according to a Monday news release.

Namazi, 51, began the hunger strike on Jan. 16 to mark the seventh anniversary of a prisoner swap with Iran that freed five other Americans while he remained detained in Evin Prison.

Namazi said last week that he was protesting to draw the attention of the Biden administration.

"I went on hunger strike because I've learned the hard way that U.S. presidents tend to rely more on their political thermometer than their moral compass when deciding whether or not to enter a prisoner deal with Iran – or indeed who to include in one," Namazi said in a statement after ending his strike. "I denied myself food for an entire week so that maybe President [Joe] Biden will recognize just how desperate the situation of the U.S. hostages here has become."

Namazi, who is classified as wrongly detained by the U.S. government, was arrested while on a 2015 business trip to Iran for "colluding with an enemy state."

"I've been Iran's prisoner for a very long time," Namazi said in Monday's statement. "I know better than most that a hunger strike is a prisoner's weapon of last resort – to be used only if our cup of endurance has truly run over and after exhausting all other options."

During his seven-day hunger strike, Namazi lost around 10 pounds and his blood pressure spiked above normal levels, according to the news release. He also suffered drops in energy and lacked the ability to focus and stay warm.

In 2016, the Obama administration negotiated the freedom of five Americans detained in Iran, but Namazi was not included.

In an open letter to President Biden that announced his hunger strike last week, Namazi wrote, "Seven years and two presidents later, I remain caged in Tehran's notorious Evin prison, holding that long overdue IOU along with the unenviable title of the longest held Iranian-American hostage in history."

White House press secretary Karine Jean-Pierre told reporters on Tuesday, "We received the letter, and our thoughts are with Namazi and his family."

"The U.S. government is continuing to work to bring him home along with U.S. citizens who are wrongfully detained in Iran, including Emad Shargi and Morad Tahbaz," Jean-Pierre said then.

A spokesperson for the State Department told ABC News after Namazi began his hunger strike last week that "our thoughts are with him and his family."

"Iran's use of wrongful detention as political leverage is outrageous, and Iran should release our wrongfully detained citizens," the spokesperson said.

Despite the negative physical effects of the hunger strike, the positive international response has renewed Namazi's hope for freedom, according to Monday's news release.

"Everyone here for the sole crime of speaking their mind and for demanding their rights and the rule of law deserves our attention and respect," Namazi said in his statement.

ABC News' Shannon K. Crawford and Cindy Smith contributed to this report.