(Adds details on Saudi shipments to United States)
By Jonathan Saul
LONDON, April 5 (Reuters) - Saudi Arabia's state oil tanker company Vela has booked at least four vessels carrying up to 8 million barrels of crude for the U.S. Gulf in the past two days, tanker fixture data showed on Thursday.
A further three tankers are scheduled to arrive in the U.S. Gulf around the end of April, ship tracking data showed.
Saudi Arabia ramped up shipments to the United States, the world's biggest oil consumer -- which has seen its economy threatened by rising fuel prices -- by 25 percent in the first quarter of this year to the highest level since mid-2008.
Market analysts and traders say much of the increase was aimed at building up inventories at Saudi Arabia's joint-venture Motiva refinery in Texas before the completion of a huge capacity expansion. Others insist part of the hike could be aimed at easing rising fuel costs in the United States, which have become a focal point during the presidential election.
Saudi Oil Minister Ali al-Naimi said last month high oil prices are unjustified and that the kingdom would like to see them lower, but offered no sign it would boost output further.
Saudi Arabian output edged up in March to 9.9 million barrels per day (bpd), according to a Reuters survey.
A tanker broker said four very large crude carriers (VLCCs) had been fixed by Vela in the past two days headed to the U.S. Gulf.
Earlier this month Vela booked at least nine VLCCs from the Middle East Gulf to the U.S. Gulf, the biggest such wave of fixtures in years.
Shipments from the OPEC kingpin to the United States jumped by nearly 300,000 bpd in the first quarter of this year to 1.45 million bpd, data from the U.S. Energy Information Administration shows.
Buoyant demand for VLCCs has helped push average earnings on the benchmark Middle Gulf to Japan route -- the major market barometer -- to their highest level in over a year to more than $40,000 a day, Baltic Exchange data showed. (Additional reporting by Matthew Robinson in New York; editing Richard Mably and Dale Hudson)