Yemen : Source says military kills 12 Al - Qaeda militants in repelling an attack . U.N. official criticizes attacks on protesters . President Saleh makes an appeal to the opposition , a ruling party official says . The opposition demands he step down immediately .
NEW : Source says military kills 12 Al-Qaeda militants in repelling an attack . U.N. official criticizes crackdown on protesters . President Saleh makes an offer to the opposition , a ruling party official says . The opposition demands he step down immediately .