UPDATE 1-China's Iran crude imports jump ahead of U.S. sanctions waiver
* China's May crude imports up 49.5 pct from April
* Iran imports jump in final month before U.S. waiver renewed
* Iran crude imports up 6.4 pct in May from year ago
* Jan-May Iran crude imports up 10 pct from same period 2012
BEIJING, June 21 (Reuters) - China's average daily crude imports from Iran jumped nearly 50 percent in May from the previous month, back around levels before sanctions were slapped on the Middle Eastern country over its disputed nuclear programme two years ago.
The jump in China's imports of Iranian crude to 555,557 barrels per day (bpd) came just before the United States renewed the country's waiver on U.S. sanctions aimed at cutting off Iran's oil revenues and bringing it to the negotiating table.
But industry sources with knowledge of China's crude imports said the surge from Iran may be due to the timings of cargo arrivals and how they were counted by the General Administration of Customs (GAC). The sources said China's two main importers - Sinopec Corp and Zhuhai Zhenrong - do not usually vary their term crude imports widely month-to-month.
China, the world's second biggest oil consumer, bought 2.36 million tonnes of Iranian crude in May, equivalent to about 555,557 bpd, data from the GAC showed on Friday.
That was up 49.5 percent from the 371,500 bpd of Iranian crude that China imported in April, the data showed. The May level rose 6.4 percent from 521,936 bpd a year earlier.
China and other buyers of Iranian oil including India, Japan and South Korea have been pressured by U.S. and European sanctions since early last year to cut imports.
The United States in early June renewed waivers on sanctions for China and other Asian countries in exchange for their reducing purchases of crude from Iran.
China's imports for the first five months of the year were up about 10 percent from the same period a year ago. The import figures for May and year-to-date contrasted sharply with China's oil shipments from Iran in 2012, when the intake of Iranian barrels was about 438,448 bpd, down 21 percent versus 2011.
The U.S. and European measures aimed at Iran's oil exports cut them to their lowest in decades in May and have been costing the country billions of dollars in lost revenue per month. Washington is now seeking to cut Iran's oil shipments further through tighter sanctions.
India, Iran's second largest customer, cut its Iranian crude imports 12.2 percent in May compared with a year ago. South Korea reduced its imports of oil from Iran by 8.3 percent from the month compared to May 2012.
China has repeatedly voiced its opposition to unilateral sanctions outside those by the United Nations, such as those imposed by the United States.
China's total crude imports in May inched up 0.4 percent from a year earlier to 5.64 million bpd, customs data showed earlier in the month.
(Reporting by Judy Hua and Fayen Wong; Editing by Tom Hogue)