Asserting that Christians are more persecuted today than at "any time since their early history," the Knights of Columbus announced here Tuesday a major expansion of its humanitarian aid efforts for Christian refugees in the Middle East, especially Syria and Iraq.

"Christians in the Middle East are facing a dire situation - even extinction," Carl Anderson, chief executive of the Catholic fraternal organization, told a news conference at the Convention Center.

"In Syria, 700,000 Christians have been internally displaced" since ISIS began a brutal campaign last year to establish military and political control of the region, he said.

An additional 125,000 Christians have fled the Iraqi city of Mosul, he said, and 70 percent of Iraq's Christian population has fled the country since 2003.

Anderson, who bears the title of grand knight, said his 1.9 million-member organization - which has donated more than $3 million in relief aid to the region's displaced Christians in the last year - is urging its 10,000 local chapters to raise awareness and funds at Catholic parishes throughout the United States.

The Knights of Columbus has created a website, ChristiansAtRisk.org, to receive donations.

About 2,000 members are in Philadelphia attending the annual convention, which began Tuesday and continues through Thursday.

The leadership has not set a financial target for the campaign or decided how long it should last, Anderson said. Donations will be used mostly to provide housing, education, and medical services for Christian refugees. All administrative costs will be absorbed by the Knights organization, he said.

Anderson was joined at the dais by the Eastern Rite Catholic archbishops of Aleppo, Syria, and Erbil, Iraq, who described the plight of their people, and urged Americans to support the project.

"My people are very scared," said Archbishop Jean-Clement Jeanbart of Aleppo. "We have seen people slaughtered. Women violated. Priests and bishops kidnapped. Churches and convents invaded."

Relief services will help them to remain in a part of the world, Jeanbart said, where Christians have been a significant presence for 2,000 years.

Archbishop Bashar Matti Warda of Erbil said ISIS militants in the last year had destroyed his cathedral, the archdiocesan offices, and numerous shrines, and were storing munitions in vacated churches.

"It is a very dangerous situation," Warda said.

Christians are not the only group being persecuted by ISIS, which is seeking to establish a caliphate, or supreme leadership, for all of the world's Muslims.

The United Nations recently said that more than 3.8 million Syrians - the great majority of them Muslim - have fled ISIS to Egypt, Jordan, Lebanon, and Turkey, and that 7.6 million more are displaced inside the country.

Anderson said in response to a question that in time, his organization might expand its relief effort to serve Muslims and other non-Christians affected by the civil war in Syria and ISIS terrorism, which has included videotaped beheadings of relief workers, soldiers, civilians, and journalists.

Andrew T. Walker, the Knights' vice president for communications, said after the news conference that the organization's last major relief effort of this scope was directed at Haiti, following the catastrophic earthquake of 2010 that killed more than 100,000.

The Knights of Columbus raised funds to provide prosthetic arms and legs to more than 1,000 children who lost limbs in the quake, Walker said.