Shiite fighters and Sunni fighters, who have joined Shiite militia groups known collectively as Hashid Shaabi ("Popular Mobilization") to fight the Islamic State, gesture Tuesday next to former Iraqi President Saddam Hussein's palaces in the Iraqi town of Ouja, near Tikrit. Thaier Al-Sudani/Reuters/Landov hide caption

itoggle caption Thaier Al-Sudani/Reuters/Landov

U.S. Secretary of State John Kerry speaks at a news conference in Sharm el-Sheikh, Egypt, on Saturday. Kerry said he's returning to nuclear negotiations with Iran with "important gaps" standing in the way of a deal. Brian Snyder/AP hide caption

itoggle caption Brian Snyder/AP

Its doubtful that Arkansas Sen. Tom Cotton (right) will face legal consequences for the letter he wrote to Iran. The Logan Act hasn't been used to prosecute anyone since it was passed more than 200 years ago. Lauren Victoria Burke/AP hide caption

itoggle caption Lauren Victoria Burke/AP

A letter from U.S. senators suggests the lawmakers "not only do not understand international law, but are not fully cognizant of the nuances of their own Constitution," says Iranian Foreign Minister Mohammad Javad Zarif. Kyodo /Landov hide caption

itoggle caption Kyodo /Landov

Iraqi security forces and Shiite fighters fire artillery during clashes with ISIS militants in Salahuddin province. The push to retake Tikrit is being aided by Iran, which is providing rockets and other support to Iraq. THAIER AL-SUDANI/Reuters /Landov hide caption

itoggle caption THAIER AL-SUDANI/Reuters /Landov

U.S. Secretary of State John Kerry goes for a stroll along the shore of Lake Geneva on Sunday prior to renewed nuclear negotiations in Geneva with his Iranian counterpart. Fabrice Coffrini/AFP/Getty Images hide caption

itoggle caption Fabrice Coffrini/AFP/Getty Images

Iranian Jewish men read from the Torah scroll during morning prayers at Youssef Abad Synagogue in Tehran in 2013. Behrouz Mehri/AFP/Getty Images hide caption

itoggle caption Behrouz Mehri/AFP/Getty Images

People ride a horse and carriage through Isfahan's central square in June 2014. With its immense mosques, picturesque bridges and ancient bazaar, the city is a virtual living museum of Iranian traditional culture and is a top tourist destination. After decades of difficult relations with the West, Iran now says it wants more foreign tourists, including Westerners. John Moore/Getty Images hide caption

itoggle caption John Moore/Getty Images

Iranians commemorate the 36th anniversary of the Islamic Revolution near the Azadi Tower in Tehran on Wednesday. While many Iranians would like to reorder relations with the West, there's also plenty of skepticism about whether it will actually happen. Ebrahim Noroozi/AP hide caption

itoggle caption Ebrahim Noroozi/AP

Argentina's Foreign Minister Hector Timerman on Jan. 15 shows a letter he said was sent in 2013 to Interpol informing it of an agreement reached with Iran's government to investigate the 1994 bombing of the Argentine-Israeli Mutual Association that killed 85 people. Timerman says he met with Iran in an attempt to solve the case and denies accusations he was part of a cover-up. Rodrigo Abd/AP hide caption

itoggle caption Rodrigo Abd/AP

Israeli Prime Minister Benjamin Netanyahu will address a joint session of Congress about Iran on March 3. The White House was not consulted on the invitation. Oded Balilty/AP hide caption

itoggle caption Oded Balilty/AP

Lebanese Hezbollah supporters carry the coffin of Jihad Mughniyeh during his funeral in Beirut on Monday. Mughniyeh was one of six ranking members of Hezbollah killed in a suspected Israeli strike Sunday. Iran says a general of its elite Revolutionary Guards was also killed. Joseph Eid/AFP/Getty Images hide caption

itoggle caption Joseph Eid/AFP/Getty Images