The International Energy Agency warned Wednesday a potential supply shortfall from Iran and Venezuela could present a "major challenge" for oil producers if they are to fend off sharp price rises and fill the gap, and reiterated its readiness to act if necessary to ensure a well-supplied market. SEE MORE Japan's economy shrank in the first quarter of 2018 for the first time in two years, ending the longest stretch of economic growth since the 1980s. SEE MORE Donald Trump's foreign policy toward China and Iran has given global markets the shivers prompting observers to lambast the White House's strategy. SEE MORE Ethylene remains long although the market has edged towards increased balance, since the spate of exports in April saw product leave Europe. SEE MORE US spot toluene prices rose 14 cents last week to close Friday at 299 cents/gal in an extremely tight market. Sources pointed to reduced extraction as a driver behind the tightness, as reformate spot prices were near just a 2-cent premium to the blend value, which was last estimated at near 255 cents/gal. SEE MORE