LOS ANGELES, May 23 (Xinhua) -- Law enforcement agents rounded up or deported more than 300 illegal immigrants in the Los Angeles area during three weeks of raids that ended this week, immigration officials announced Friday.

    The arrests were part of raids that were conducted across California, in which 905 illegal immigrants were arrested, officials said.

    The majority of the 327 people who were arrested in the Los Angeles area were immigrants who had ignored final orders of deportation or who re-entered the United States after being deported, U.S. Immigration and Customs Enforcement (ICE) spokeswoman Tammy Wilson said.

    About a quarter of the immigrants arrested in Southern California had criminal histories besides being in the country illegally, Wilson said.

    The latest round of raids and arrests ended Thursday, Wilson said.

    More than half of those arrested during the recent ICE operation were immediately removed from the United States because they had already been ordered deported, Wilson said. The remaining suspects are in custody and awaiting court dates before an immigration judge or are waiting for ICE to arrange their deportation, Wilson said.

    "ICE is committed to protecting the integrity to this country's immigration system and that means ensuring that the removal orders handed down by the nation's immigration courts are carried out," said Brian DeMore, acting field officer director for ICE detention and removal operations in Los Angeles.

    The nation's fugitive alien population has decreased for the first time ever, ICE said. Estimates place the total number of fugitive immigrants at just under 573,000 -- a decrease of more than 59,000 since October 2006, ICE said.