(File photo: AP)

HOUSTON, April 7 (Xinhua) -- Oil prices increased during the week ending April 5, with the price of West Texas Intermediate (WTI) for May delivery up 4.89 percent and Brent crude oil for June delivery up 2.85 percent.

At the end of the week, WTI settled up at 63.08 US dollars a barrel on the New York Mercantile Exchange, while Brent crude closed up at 70.34 dollars a barrel on the London ICE Futures Exchange.

WTI and Brent have increased 38.91 percent and 30.74 percent, respectively, so far this year, mainly due to the on-going efforts to curb supply by major oil producers.

During the week, WTI and Brent by and large moved towards same directions except on Thursday, when WTI was down 0.36 dollar to settle at 62.10 dollars a barrel while Brent was up 0.09 dollar to close at 69.40 dollars a barrel.

The oil prices mix came amid military escalation in Libya and an unexpected increase in US crude oil inventories.

On Monday, as a latest survey showed the Organization of the Petroleum Exporting Countries (OPEC) lowered its daily production in March, easing concerns over a potential global oversupply, and official data showed Russia oil production fell in March, WTI rose 1.45 dollars to settle at 61.59 dollars a barre, while Brent crude increased 1.43 dollars to close at 69.01 dollars a barrel.

On Tuesday, oil prices extended gains.

Oil prices decreased on Wednesday, as US crude oil inventories surprisingly increased in the previous week. WTI decreased 0.12 dollar to settle at 62.46 dollars a barrel, while Brent crude decreased 0.06 dollar to close at 69.31 dollars a barrel.

According to the US Energy Information Administration (EIA), for the week ending March 29, US commercial crude oil inventories increased by 7.2 million barrels from the previous week. At 449.5 million barrels, US crude oil inventories are at the five-year average for this time of year, the EIA said in its latest weekly report released on Wednesday.

The unexpected growth came alongside rising imports, as US crude oil imports averaged 6.8 million barrels per day (bpd) last week, up by 223,000 bpd from the previous week, said the report.

The increase report defied market expectation, which forecast a drawdown of 0.43 million barrels of crude oil inventories in the country. The surprising buildup of inventories implied weaker demand and more pressure on crude prices.

Oil prices rallied on Friday, amid strong US employment data, easing worries over weakening oil demand due to potential economic slowdown.

Oil prices have kept gaining momentum since beginning of the year. However, a rising US dollar has dragged down the greenback-denominated crude futures, as the US Dollar Index has been keeping uptrend in the last 12 months. US Dollar Index firmed above 97.00, consolidating weekly gains.

The US Dollar Index is a measure of the value of the US dollar relative to a basket of foreign currencies. Oil is mostly traded in dollars all over the world and a stronger dollar pressures the oil demand.

In the near future, demand growth and geopolitical issues are important factors to affect oil prices. Both OPEC and the International Energy Agency believe the world oil demand will keep uptrend in coming years.