WASHINGTON, July 30 (Reuters) - Religious freedom in Egypt appears to be "quite tenuous" and its government has failed to aggressively prosecute perpetrators of sectarian violence, U.S. Secretary of State Hillary Clinton said on Monday.

Clinton made the comment as the State Department released a report that found a marked deterioration in religious freedom in China, where official interference with Tibetan Buddhist monasteries may have contributed to a dozen self-immolations.

In its annual International Religious Freedom Report for 2011, the State Department also said it discerned a rise in global anti-Semitism as well as the increased use of anti-blasphemy laws to restrict the rights of religious minorities.

The report gave particular attention to countries where last year's "Arab Spring" of popular protests unseated authoritarian rulers such as former Egyptian president and long-time U.S. ally Hosni Mubarak.

"I am concerned that respect for religious freedom is ... quite tenuous" in Egypt, Clinton said in response to a question after she gave a speech at a Washington think tank, saying sectarian violence had increased since Mubarak's downfall but the authorities had been inconsistent in prosecuting it.

"That then sends a message to the minority community in particular, but to the larger community, that there's not going to be any consequences," she said.

Clinton got a first-hand taste of the bitterness of many Egyptian Christians at this year's election of Islamist Mohammed Mursi as president of the country, with protests by angry Copts, among others, outside her Cairo hotel.

Unknown protesters also pelted her motorcade with tomatoes, shoes and water bottles in the Mediterranean city of Alexandria.

The report covers 2011 and therefore does not assess the authorities' performance since Mursi's election brought an Islamist to power in the Arab world's most-populous nation.

'EGREGIOUS SITUATION' IN IRAN

The report said it had documented the Egyptian government's "failure to curb rising violence against Coptic Christians and its involvement in violent attacks," citing an Oct. 9, 2011 incident in which security forces attacked Cairo demonstrators.

The report said 25 people were killed and 350 injured, most of them Coptic Christians. "To date, government officials have not been held accountable for their actions and there were indications in early 2012 of mounting Coptic emigration," it said.

The report said conditions worsened in Iran, where it cited state "imprisonment, harassment, intimidation and discrimination based on religious beliefs," as well as in Pakistan, where "abuses continued under the blasphemy law."

The State Department also cited "a marked deterioration" in official respect for and protection of religious freedom in China, including greater restrictions on religious practice especially in Tibetan Buddhist monasteries and nunneries.

"Official interference in the practice of these religious traditions exacerbated grievances and contributed to at least 12 self-immolations by Tibetans in 2011," the report said.

In Iran, with which the United States has had acrimonious relations since the 1979 Islamic Revolution, religious freedom "deteriorated further from an already egregious situation," the State Department said.

It cited the restoration of 20-year sentences for seven Bahais charged with spying for and collaborating with Israel as well as the imprisonment of Yousof Nadarkhani, a Christian pastor sentenced to death for apostasy.