The United States warned the world was sliding backwards on religious freedoms Monday, slamming China for cracking down on Tibetan Buddhists and hitting out at Pakistan and Afghanistan.

As the State Department unveiled its first report on religious freedoms since the start of the Arab Spring, Secretary of State Hillary Clinton said it was a "signal to the worst offenders" that the world was watching.

"New technologies have given repressive governments additional tools for cracking down on religious expression," Clinton told a US think-tank, adding that pressure was rising on some faith groups around the globe.

"More than a billion people live under governments that systematically suppress religious freedom," she stressed.

"When it comes to this human right -- this key feature of stable, secure, peaceful societies -- the world is sliding backward."

The 2011 International Religious Freedom Report noted that last year governments increasingly used blasphemy laws to "restrict religious liberty, constrain the rights of religious minorities and limit freedom of expression."

In China "there was a marked deterioration during 2011 in the government's respect for and protection of religious freedom in China," the report said.

This included "increased restrictions on religious practice, especially in Tibetan Buddhist monasteries and nunneries."

"Official interference" in traditional Tibetan religious practices had "exacerbated grievances and contributed to at least 12 self-immolations by Tibetans in 2011."

China's has not yet given an official response, but a Xinhua commentary said there was "no justification" for the criticism and accused the United States of "blatantly interfering in the internal affairs of other countries".

"The US action will only backfire by creating more suspicion and distrust rather than fostering mutual understanding and improving relations with other countries," said Xinhua.

China and North Korea, where the report noted that religious freedom does not exist in any form, along with Myanmar are among eight nations designated as "countries of particular concern" for failing to accept religious rights.

They are accompanied by Eritrea, Iran, Saudi Arabia, Sudan and Uzbekistan.

Highlighting the situation in Indonesia and Afghanistan, the report recalled the case in Pakistan of Aasia Bibi, the first Christian woman to be sentenced to death for blasphemy in the country.

And while in Afghanistan the constitution says that followers of other religions are free to worship as they please it also maintains "that Islam is the 'religion of the state,'" the report said.

The Afghan government's "failure to protect minority religious groups and individuals limited religious freedom," it insisted.

Much of the focus of the 2011 report however was on the countries involved in the Arab Spring, where popular uprisings have ousted autocratic leaders.

Despite gestures by Egypt's interim military leaders towards greater inclusiveness, sectarian violence had increased, the report said, denouncing "both the Egyptian government's failure to curb rising violence against Coptic Christians and its involvement in violent attacks."

Clinton, who visited Egypt earlier this month, said she had had "a very emotional, very personal conversation with Christians who are deeply anxious about what the future holds for them and their country."

Egypt's new leader, President Mohamed Morsi, who emerged from the Islamic Brotherhood to become the country's first democratically-elected president, had vowed in their talks "to be the president of all Egyptians."

But Christians were asking "will a government looking explicitly to greater reliance on Islamic principles stand up for non-Muslims and Muslims equally? Since this is the first time that Egypt has been in this situation.

"It's a fair question," Clinton said.

The report also warned that European nations undergoing major demographic shifts have seen "growing xenophobia, anti-Semitism, anti-Muslim sentiment, and intolerance toward people considered 'the other.'"

It complains of a "rising number of European countries, including Belgium and France, whose laws restricting dress adversely affected Muslims and others."