NEW YORK ( TheStreet) -- Crude prices slipped below $80 a barrel as concerns about China and a strong U.S. dollar pressured energy prices Monday.

After settling above $80 a barrel for eight consecutive sessions, crude prices bucked the trend Monday, losing $1.44, or 1.8%, to settle at $79.80 a barrel.

The United States Oil Fund ETF ( USO) shed 1.7%, to $38.85 and the PowerShares DB Oil Fund ETF ( DBO) dropped 1.6%, or 44 cents, to close at $27.09.

Darin Newsom, senior commodities analyst at Telvent DTN, said market observers are keying on China, currency and inflation issues today.

In particular, he said traders are "keeping a close eye on the dollar" this week. The Federal Reserve's policy-making arm will release its closely-scrutinized statement on Tuesday afternoon, which market watchers will scour for any changes in language and hints at when a rate hike can be expected.

U.S. equities were mired in negative territory throughout the morning session on fears that the U.S and U.K.'s top-notch credit ratings may be in jeopardy after reports said Moody's Investors Service suggested as much.

Investors sought safety in the dollar, which put pressure on commodities. The dollar index rose 0.5%.

Comments from Chinese Premier Wen Jiabao over the weekend indicating that the yuan will remain stable poured cold water on chatter to allow the yuan to appreciate against the dollar; concerns about Chinese monetary tightening also weighed on commodities.

"What's interesting to me is that we made a run to the January high last week," Newsom said. "But, again, a lack of fundamental support and the higher dollar and everything turns down."

A better-than-expected read on New York State manufacturing activity and unexpected growth to industrial production and capacity utilization during a month that saw Northeastern states battered by severe weather did little to lift market sentiment during the morning session, although the Dow Jones Industrial Average and the S&P 500 managed to finish ahead by the close of trading.

Energy-related equities turned in the poorest performance among the major sectors today. The NYSE Arca Oil index went lower by 0.7%, while the Philadelphia Oil Service Sector index slid 1.2%.

Exxon Mobil ( XOM) shares lost 0.8%, to $66.30, landing it among the Dow's top three biggest laggards. Chevron ( CVX) didn't fare much better, with shares off by 0.2%, to $73.57.

But a deal announcement also took one of the biggest headlines in the energy space today, as Dominion ( D) agreed to sell natural gas assets to Consol Energy ( CNX) for $3.4 billion. Consol's stock was one of the New York Stock Exchange's worst performers, with shares shedding $5.48, or 10.1%, to $48.85. Dominion's stock, meanwhile, was higher by 2 cents, or 0.05%, at $39.71.

Shares of Apache Corp ( APA) lost $2.53, or 2.4%, to $104.32 as an analyst at Morgan Stanley downgraded the company, citing expectations for lower earnings on weak natural gas prices.

Natural gas for April delivery lost a penny, or 0.2%, to settle at $4.39 per million British thermal units, and shares of natural gas producers finished the session broadly lower. Gastar Exploration ( GST) lost 2.6%, Devon Energy ( DVN) lost 2.6% and Chesapeake Energy ( CHK) was down by 0.9%.

Elsewhere on the Nymex, the April heating oil contract dipped 4 cents, or 1.7%, to$2.06 a gallon, and the April gasoline contract lost 3 cents, or 1.4%, to $2.22 a gallon.

--Written by Sung Moss and Melinda Peer in New York.