* Top four buyers take 1.15 mln bpd of Iranian crude in March
* Tanker data shows Asia's Iran imports dropping further over coming months
* Lower crude exports from Iran could add to support for oil prices
By Osamu Tsukimori
TOKYO, April 30 Iran's top oil clients cut their March imports 16.4 percent from the previous month's two-year high and look set to reduce their shipments further over coming months, bringing the volumes closer in line with the deal easing sanctions on Tehran.
Under the November agreement that took effect in January, Iran's oil shipments were to remain at an average 1 million barrels per day (bpd) for the six months to July 20, although Asian imports alone have averaged more than that this year.
But after Asian imports of Iranian oil hit their highest since early 2012 in February, arrivals have started to fall, with tanker loading schedules showing that intakes over the next two months can be expected to come closer to the deal's mark.
In March, Iran's top four clients - China, India, Japan and South Korea - imported 1.15 million bpd of Iranian crude and condensate, down from 1.37 million bpd in February, according to official data and tanker arrival schedules given to Reuters.
"The decrease is probably not due to pressure from the West but this should have more to do with (a fall) in actual demand as refineries enter maintenance," said Ken Hasegawa, a commodity sales manager at brokerage Newedge Japan.
The United States privately warned India earlier that it needed to hold its Iran oil buys to end-2013 levels, but there have been few signs of pressure on other buyers of the oil.
Many Asian refiners target the March-May period for plant maintenance, as consumer demand dips between peak winter and summer use, and overall crude imports usually drop off.
On Tuesday, in a possible sign of greater pressure to come on sanctions busters, the United States announced charges against a Chinese businessman for violating sanctions laws on Iran. The U.S. Treasury also said it was sanctioning a Dubai-based entity for helping others to evade measures to limit Iran's oil sales.
The Obama administration has said it believes that Iran's oil sales will fall in coming months and average 1 million bpd over the entire six-month period to July 20.
Asian buyers' crude imports from Iran in February were the highest since January 2012 as refiners took in more crude to replace stocks depleted by winter demand.
And while Iran's rising exports over the last few months have helped cap oil prices boosted by supply concerns in Libya and the escalating crisis in Ukraine, the expected cutbacks in exports in the coming months should now give added support to benchmark Brent prices.
Tanker loading schedules seen earlier by Reuters have indicated that the import volumes can be expected to fall for the next couple of months, with Japan receiving little or no oil in April and South Korea importing little to none in May.
In March, Iran's top four oil clients still imported 14.7 percent more than in the same month last year, while imports of Iranian crude in the first quarter at 1.25 million bpd were up 18 percent from a year ago.
India's imports last month more than doubled from a year ago to 387,000 bpd, despite the earlier U.S. warning for it to keep its Iran imports at end-2013 levels of about 195,000 bpd.
Iran's biggest oil customer, China, lifted its imports by 36.1 percent from a year ago to 555,182 bpd in March, while South Korea's crude imports fell 50.6 percent to 64,065 bpd.
Iranian imports by Japan - which was the last of the four to report its oil intake - fell 50.7 percent to 139,476 bpd last month, trade ministry data showed on Wednesday.
The United States and the European Union toughened sanctions on Tehran in early 2012 in an effort to force it to end its nuclear programme, slashing the Islamic republic's oil exports by more than half and costing it billions a month in revenue.
After an interim deal was reached in November last year, Tehran agreed to curtail its uranium enrichment programme in exchange for an easing of sanctions, including the repatriation of some $4.2 billion in frozen oil funds.
Negotiators from Iran and the United States, Russia, China, Britain, France and Germany, known as P5-plus-one, will begin a round of talks in Vienna next month to finalise an end to the decade-old nuclear dispute. (Additional reporting by James Topham; Editing by Tom Hogue)