Oil prices were up nearly a dollar in Asian trade on Thursday after President Donald Trump announced a blockade on tankers entering and leaving Venezuela and most exports from the country remained on hold. US West Texas Intermediate (WTI) crude was up 98 cents, or 1.7%, at $56.89 per barrel at 0120 GMT, after initially rising more than a dollar. Brent crude rose 92 cents or 1.54% to $60.60 per