he screening process, which has faced domestic criticism, is "rigorous and exhaustive," said Anne Richard, assistant secretary of state for population, refugees and migration.

Highly trained officers conduct the screening to ensure that applicants aren't terrorists, said León Rodriguez, director of U.S. Citizenship and Immigration Services, an agency of the Department of Homeland Security.

"Hundreds [from Syria] have been denied," Rodriguez told reporters in a conference call along with Richard and Robert Carey, director of refugee resettlement for the Department of Health and Human Services.

Goal within reach

The United States is on track to meet President Barack Obama's goal of allowing in 10,000 refugees from Syria for the fiscal year ending in September, the officials said.

"We may exceed 10,000, and for next year we will continue to welcome large numbers of Syrians, but it's too soon to have a target figure established," Richard said.

Nearly 80 percent of the Syrians accepted this year by the United States are women and children, officials said.