U-S Immigration and Customs Enforcement agents rounded up 39 convicted criminal aliens during an operation last week in Eastern Mass., including in New Bedford.  Ice officials say 20 of the suspects had felony convictions for such crimes as assault and battery, sexual assault, and selling drugs.  The aliens range in age from 18 to 52,  are being held pending immigration removal proceedings or deportation.  According to a release, ice prioritizes the arrest of immigration fugitives or criminal aliens who have been previously deported, and illegally re-entered the country.