days and some say, they may only have enough oxygen for two more days at the most? >> reporter: that's right, david. the argentine navy says in a worst case scenario, if the submarine has sunk, it only has a total of a week's worth of oxygen. david? >> linzie janis in argentina. linzie, thank you. president trump putting north korea back on the list of state sponsors of terror tonight, calling it a, quote, murderous regime. and promising new sanctions and penalties. secretary of state rex tillerson today calling that designation a, quote, very symbolic move, saying that sanctions already in place are working. saying that the two-month pause since north korea's last missile test shows that there is still hope for diplomacy. the department of justice tonight rejecting at&t's bid to buy time warner. the mega-merger worth $85 billion. the doj claiming the merger would hurt american consumers. tonight, at&t says they plan to counter-sue. we turn next here to an abc news exclusive tonight. the american mother and her family held captive by the taliban for years. in her first television interview, describing the brutal