Washington says in its International Religious Freedom Report for 2013 that North Korea is the world's most repressive government due to its prohibition of religious organizations and punishments of any unauthorized religious activities.
The U.S. State Department report, released on July 28, also says countries such as Iran, Saudi Arabia, and Sudan in 2013 "put severe restrictions on members of religious groups that did not conform to the state-approved religions."
It notes that in Tajikistan, Turkmenistan, Uzbekistan, China, and Cuba, "religious activity was only lawful if explicitly authorized by the state."
The report faults Pakistan for continuing to enforce blasphemy laws and says the governments of Iraq and Syria have failed to protect vulnerable religious communities from persecution by extremist groups.
It also says that in Russia the government used a new law against "extremism" and amendments to existing laws to further restrict the activities of members of minority religious groups, including making it illegal for foreigners to participate in religious organizations.
It adds that the Russian government continued to grant the Russian Orthodox Church a privileged position.
Looking worldwide, the report says that in 2013 the world witnessed the largest displacement of religious communities in recent memory.
In almost every corner of the globe, the report notes, millions of Christians, Muslims, Hindus, and others representing a range of faiths were forced from their homes on account of their religious beliefs.
It says mass displacement of religious minorities in conflict zones has become a "pernicious norm," noting that in Syria and much of the Middle East the Christian presence is becoming "a shadow of its former self."
The report notes that in the Central African Republic sectarian violence between Christians and Muslims resulted in the displacement of more than one million people during 2013.
The International Religious Freedom Report is released annually by the U.S. State Department in an effort to attract global attention to the problem of repression of religious freedom.
The report quotes U.S. President Barack Obama as noting that "history shows that nations that uphold the rights of their people -- including the freedom of religion -- are ultimately more just and more peaceful and more successful. Nations that do not uphold these rights sow the bitter seeds of instability and violence and extremism."