In Rochester, Michigan, the Arizona senator used a wide-ranging speech on human dignity to promise support for religious freedom in countries that imprison or persecute "tens-of-thousands of people whose only crime is to worship God in their own way."

"As president, I intend to make religious freedom a subject of great importance for the United States," McCain told an audience at Oakland University, where he was met by protesters against his pro-Iraq war policies toting placards saying "War Sucks" and "Who Wants Peace Anyway?"

"Whether in bilateral negotiations, or in various multinational organizations to which America belongs, I will make respect for the basic principle of religious freedom a priority in international relations," he added, mentioning China, Iran, Myanmar, Sudan, North Korea and Saudi Arabia as countries where people face religious persecution.

McCain has angered Republican conservatives in the past with his moderate positions on immigration, campaign finance reform and other issues. But since clinching the nomination he has been working to unify the party behind his candidacy before facing the Democratic nominee -- either Illinois Sen. Barack Obama or New York Sen. Hillary Clinton -- in the November election.

McCain told supporters Wednesday he would also do more to clamp down on international human trafficking, which he called a "modern day slave trade" mostly linked to the sex trade.

"Inexcusably, it is a crime that, while prevalent elsewhere, exists within our own borders as well," he added.

A 2004 State Department report estimated up to 800,000 adults and children are trafficked across international borders each year, with as many as 18,000 brought into the United States, "many of whom are forced into the sex trade," McCain said.

"Most of the victims of human trafficking in the United States and in most other places in the world are the most vulnerable among us, destitute women and children who are sold into bondage as sex slaves," he said.

McCain called for increased cooperation with other countries, and pledged to set up a task force on human trafficking that would report directly to him. He also promised to aid victims of the trade.

"We will take care to show compassion for victims of this despicable crime against humanity by making sure shelter, counseling and legal assistance is available and accessible to them," he added.

McCain also pledged to crackdown on Internet child pornography.