"Individuals who dissent from the prevailing orthodoxy regarding Islamic beliefs and practices are subject to legal actions that violate international standards," according to the commission, which was created in 1998 to review violations of religious freedom internationally and make policy recommendations to the U.S. government.
"The Taliban and other non-state actors continue to target individuals for activity deemed 'un-Islamic,' and the Afghanistan Constitution fails explicitly to protect the individual right to freedom of religion or belief."
An Afghan government official disputed the findings.
"The Afghan government is fully committed to ensuring religious freedom for followers of all religions in Afghanistan, something our constitution is very clear about," Janan Mosazai, spokesman for the Afghan Foreign Ministry, said in an email to The Associated Press. Mosazai said that even though Islam is Afghanistan's official religion, the constitution clearly states that "followers of other faiths shall be free within the bounds of law in the exercise and performance of their religious rituals."
In its 2013 annual report, USCIRF praises that clause of Afghanistan's 2004 constitution, but notes that another part of the charter says these fundamental rights can be superseded by ordinary legislation. This shortcoming is compounded by "a vague, repugnancy clause" that says no law can be contrary to Islam and allows courts to enforce it, the commission says.
In addition, the penal code discriminates against minorities by allowing courts to defer to Shariah, or Islamic law, in cases involving matters such as apostasy and conversion that are not explicitly addressed by the penal code or the constitution, resulting in those charges being punishable by death, the report says.
Because of legal restrictions, USCIRF says, "Afghans cannot debate the role and content of religion in law and society, advocate for the rights of women and religious minorities, or question interpretations of Islamic precepts without fear of retribution or being charged with religious 'crimes' such as apostasy, blasphemy or insulting Islam."
Religious freedom is especially repressed in areas heavily controlled by the Taliban, which governs by their own interpretation of Islamic law, the report said.
It cited two cases in 2010-2011 during which Afghans accused of converting to Christianity were prosecuted in the courts for apostasy, but later released. USCIRF also noted that marriage is formally restricted to Muslims and that non-Muslims are allowed to marry as long as they do not publicly express their faith.
"The few Afghan Christians, converts from Islam or their children, long have been forced to conceal their faith and cannot worship openly," the report said. "The situation for Christians worsened in 2010, when authorities arrested 26 Christians. After their release, many fled to India, where they have applied for refugee status due to a fear of religious persecution."
Despite restrictions on religious freedom, Afghanistan has been largely spared the sectarian violence that has rocked Iraq and neighboring Pakistan.
Afghanistan recorded its first major sectarian assault since the fall of the Taliban regime in December 2011, when a suicide bomber slaughtered 56 Shiite worshippers and wounded more than 160 outside a Shiite shrine in the capital. The Taliban condemned the attack, and suspicion about who was to blame centered on militant groups based in Pakistan, where Sunni attacks on minority Shiites are common.
Some violence in Afghanistan, however, does have religious overtones.
In November 2012, Sunni and Shiite students clashed at Kabul University on a Shiite holy day, and at least one person was killed. That same month, Afghan security personnel and residents reportedly prevented Sikhs from performing cremation ceremonies for their deceased relatives, the report said.
In an earlier court case not cited by USCIRF, Sayed Parwez Kambakhsh, a journalism student, was condemned for blasphemy in 2008, for distributing material found on the Internet questioning women's rights under Islam, and sentenced to death. However, a court later commuted the sentence to 20 years and President Hamid Karzai then pardoned the student.
Mosazai said the state of religious freedom in Afghanistan today must be compared with the suffering and brutality that people of all faiths endured during the 1990s, first during the civil war, then under the Taliban regime.
He praised USCIRF for a passage in the report saying that since then, "conditions for religious freedom have markedly improved, especially for religious minorities."
USCIRF concludes its report by recommending that the U.S. and its allies "increase and strengthen diplomatic, development and military engagement to promote human rights, especially religious freedom." It also urges the U.S. to raise directly with Karzai "the importance of religious freedom, especially for dissenting Muslims, Muslim minorities and non-Muslim minorities."