Tehran on Saturday blasted U.S. President Donald Trump'stravel ban on countries including Iran, saying it showed "deep hostility" toward Iranians and Muslims.

Iranians again face a U.S. travel ban imposed by President Donald Trump, with the decision drawing anger, frustration and some shrugs given the decades of tensions between the countries.

Here is a closer look at why the administration says it is instituting full bans on foreign nationals traveling to the U.S. from 12 nations.