Here's a look at what you need to know about some recent cases of foreign governments detaining U.S. citizens.
Alan Gross December 2009 - Alan Gross is jailed while working as a subcontractor on a U.S. Agency for International Development project aimed at spreading democracy. His actions are deemed illegal by Cuban authorities. He is accused of trying set up illegal Internet connections on the island. Gross says he was trying to help connect the Jewish community to the Internet and was not a threat to the government.
August 2010 - While on a trade mission in Cuba, New Mexico Gov. Bill Richardson presses Cuba to free Gross.
March 12, 2011 - Gross is found guilty and sentenced to 15 years in prison for crimes against the Cuban state.
March 30, 2011 - Former President Jimmy Carter visits Cuba and tries to secure Gross' release on humanitarian grounds, arguing that Gross' mother and daughter are battling cancer. He is unsuccessful.
September 7-14, 2011 - Bill Richardson visits Cuba on a private mission to win the release of jailed American contractor Alan Gross. He is unsuccessful.
February 18-20, 2013 - A U.S. congressional delegation, led by Senator Patrick Leahy, visits Cuba and meets with Raul Castro in an effort to free Gross. They are unsuccessful.
16 American NGO Employees December 2011 - Egyptian authorities carry out 17 raids on the offices of 10 nongovernmental organizations. The Egyptian general prosecutor's office claims the raids were part of an investigation into allegations the groups had received illegal foreign financing and were operating without a proper license.
February 2, 2012 - In a letter to Secretary of State Hillary Clinton and Defense Secretary Leon Panetta, 41 members of Congress urge the administration to withhold further aid to Egypt until the country's leadership lets the offices of those organizations reopen and returns seized property.
February 5, 2012 - Forty-three people, including 19 Americans, face prosecution in an Egyptian criminal court on charges of illegal foreign funding as part of an ongoing crackdown on NGOs. The defendants include 19 Americans, five Serbs, two Germans, three Arabs and Egyptians. Among the American defendants is Sam LaHood, International Republican Institute country director and the son of U.S. Transportation Secretary Ray LaHood.
February 15, 2012 - U.S. State Dept. confirms there are 16 Americans being held not 19 as the Egyptian government had announced.
February 20, 2012 - South Carolina Senator Lindsey Graham and Arizona Senator John McCain meet with top Egyptian military and political leaders in Cairo. In an interview with CNN, Senator Graham says that he is optimistic for a positive resolution in the near future.
February 26, 2012 - Formal reading of the charges against the NGOs. None of the sixteen detained Americans appear in court.
February 29, 2012 - The travel ban is lifted.
March 1, 2012 - A group from the 43 detainees including American, Norwegian, German, Serbian and Palestinian activists leave Cairo after each posted 2 million Egyptian pounds bail.
March 8, 2012 - Trial resumes and is adjourned until April 10. Robert Becker, an employee of the National Democratic Institute (NDI), is the lone American to appear in court.
April 10, 2012 - Trial is adjourned.
April 20, 2012 - CNN is told Egyptian officials have filed global arrest notices with Interpol for some of the Americans involved in the NGO trial.
June 5, 2012 - The trial resumes and among the defendants to appear in court are two Americans; Sherif Mansour, a recently naturalized American citizen born in Egypt and former employee of Freedom House, and Robert Becker, formerly with National Democratic Institute (NDI).
June 4, 2013 - An Egyptian court sentences a total of 43 NGO workers, including several Americans and other foreigners. The court sentences 27 NGO workers in absentia to five-year sentences; 11 to one-year suspended jail sentences; and five others to two-year sentences that were not suspended, according to state-run newspaper Al Ahram.
UC-Berkeley Grads July 31, 2009 - Three graduates from the University of California at Berkeley, Sarah Shourd of Oakland, California, Shane Bauer, of Emeryville, California, and Joshua Fattal, of Cottage Grove, Oregon, are detained in Iran after hiking along the unmarked Iran-Iraq border in northern Iraq's Kurdish region.
August 11, 2009 - Iran sends formal notification to the Swiss ambassador that the three American hikers have been detained. Switzerland represents the United States diplomatic interests in Iran since the U.S. and Iran do not have diplomatic relations.