The number of sanctuary cities in the U.S. has risen to 340, a sharp increase since July, when 276 jurisdictions had policies in place to protect illegal immigrants from deportation by refusing to comply with federal immigration authorities.

The sanctuary cities are responsible for releasing an average of 1,000 illegal criminal aliens per month, according to a new report by the Center for Immigration Studies (CIS) based on data from the Department of Homeland Security.

Between Jan. 1 and Sept. 30, 2014, local sanctuary cities freed 9,295 illegal immigrants, ignoring detainer requests that U.S. Immigration and Customs Enforcement (ICE) had placed on the immigrants so that it could begin deportation proceedings once local officials released the immigrants from custody. Over 600 of those aliens were released at least twice by local authorities, according to CIS.

One particularly concerning violent immigrant who is now roaming the streets thanks to a sanctuary city is Javier Chavez, who was arrested in August 2015 for brutally beating the 2-year-old daughter of his girlfriend, breaking both her arms and a leg. Chavez has felony drug and drunk driving convictions and a previous deportation. ICE had placed a detainer request on him, but the San Luis Obispo County Sheriff's Office chose to release him after he posted bail, even though California law would have allowed officials to continue holding him due to his illegal status.

Most of the illegal aliens released by sanctuary cities have not been re-apprehended by ICE. As of last year, 69 percent of them, or 6,460, were still at large. Of those, 3,802 had prior felonies or violent misdemeanors, according to CIS.

"An alarming number - 2,320 - of the total number of released offenders were subsequently arrested within the time period studied for new crimes after they were released by the sanctuaries," wrote Jessica Vaughan, director of policy studies at CIS.

Most of the jurisdictions that ignored ICE detainer requests are in California:

"Our elected officials must not sit back and watch these sanctuary jurisdictions continue to release thousands of criminal aliens back into our communities in defiance of ICE efforts to deport them, and then witness the harm that inevitably ensues when these removable offenders strike again," said Vaughan, according to WND.

Senate Majority Leader Mitch McConnell, R-Ky., announced Thursday that next week, the Senate will consider legislation that would restrict federal funding from going to sanctuary cities, or jurisdictions that do not comply with ICE detainer requests, reported Breitbart.