UPDATE 10-Brent plunges to 5-month low on China, Europe factory data

* U.S. crude inventories seen up 1.1 mln barrels -POLL

* China March PMI at 50.3 vs February's 50.2 -govt

* Libyan rebels say may restart 3 oil ports - state media

* Coming up: API weekly oil stocks data at 4:30 p.m. EDT

(Updates prices, oil inventory forecasts)

NEW YORK, April 1 (Reuters) - Brent crude oil futures fell to their lowest settlement in nearly five months on Tuesday as poor manufacturing data from China and Europe weighed, and U.S. oil futures fell in anticipation of another build in domestic supplies.

Chinese factory activity edged up in March, but not by enough to extinguish worries that the country, the world's No. 2 oil consumer, had a sharper-than-expected slowdown at the start of the year.

Growth in euro zone factories cooled too and companies have returned to cutting prices in order to drum up business.

U.S. commercial crude stocks were forecast to have risen for the 11th straight week in a row, boosted by a rebound in imports expected as a major oil tanker shipping channel to the Gulf Coast reopened after an oil spill.

Industry group the American Petroleum Institute will release its inventory report later on Tuesday at 4:30 p.m. EDT (2030 GMT), followed by official data from the U.S. Energy Information Administration on Wednesday at 10:30 a.m. EDT (1430 GMT).

Further weighing on Brent, Libya looked as though it might re-open three ports in the east of the country, which accounted for exports of 600,000 barrels per day (bpd) before they were occupied by rebel groups last summer.

Brent crude settled $2.14 lower at $105.62 per barrel, its lowest settlement since Nov. 8. U.S. crude fell $1.84 to $99.74 per barrel.

"Crude is being pressured by the disappointing China data and expectations for further crude oil inventory builds in the United States," said John Kilduff, partner at Again Capital LLC in New York. "There was a technical breakdown as well with U.S. crude pushing below the 200 and 50-day moving averages."

U.S. crude fell to a session low of $99.47 per barrel, below two key technical levels, the 200-day moving average at $100.49 per barrel and the 50-day moving average at $99.91 per barrel.

Once a price falls below technical levels, it continues to slide lower, Kilduff said.

Brent's premium over U.S. crude <CL-LCO1=R> tightened 30 cents to settle at $5.88, the narrowest settlement since Oct. 4.

On Monday, a leader with a Libyan rebel group in the east of the country told state media they may be close to reopening key oil ports there.

Libya's oil exports have fallen to less than 100,000 bpd from a post-civil war peak of more than 1 million bpd as armed militias and protesters seized and blocked facilities.

Investors also continued to watch the Ukraine crisis, which has raised fears of possible supply disruptions from Russia, the world's second-largest oil exporter.

In a gesture that could ease tension in the worst East-West stand-off since the Cold War, Russia pulled some troops back from near Ukraine's eastern frontier, a move the United States said would be a positive sign if confirmed as a withdrawal.

U.S. crude oil stocks are expected to have risen 1.1 million barrels on average for the week ending March 28, despite an expected uptick in refinery runs, while inventories of refined oil products were projected to have fallen, a preliminary Reuters poll showed.

Analysts said Tuesday's price falls will likely flatten out.

"We are lined up for bearish stockpile numbers, but we're not necessarily at the start of a crater," said Phil Thompson, director of Mobius Risk Group in Houston. "(Tuesday's) moves are a little bit exacerbated because liquidity is dropping."

(Additional reporting by David Sheppard in London and Florence Tan in Singapore; editing by David Evans, Jane Baird, David Gregorio and Marguerita Choy)