(Updates with Fed rates decision, market reaction)
* Retail sales increase 0.1 percent in February
* Core retail sales rise 0.1 percent, January revised up
* Consumer prices edge up 0.1 percent in February
* CPI accelerates 2.7 percent from year ago
By Lucia Mutikani
WASHINGTON, March 15 (Reuters) - U.S. retail sales recorded their smallest gain in six months in February amid delays in tax refunds, but the biggest rise in the annual inflation rate in nearly five years pointed to rising price pressures that could support further interest rate hikes.
The marginal increase in retail sales reported by the Commerce Department on Wednesday was the latest sign the economy lost further momentum in the first quarter. Firming inflation and a tight labor market encouraged the Federal Reserve to raise rates on Wednesday for the second time in three months.
"Should inflation continue to firm and consumer spending remain solid, we expect the Fed will hike again in June, and at least three times this year," said Michael Hanson, chief economist at TD Securities in New York.
The Commerce Department said retail sales edged up 0.1 percent last month, the weakest reading since August, amid declines in purchases of automobiles and discretionary spending.
January's retail sales were, however, revised up to show a 0.6 percent rise instead of the previously reported 0.4 percent advance. That left retail sales rising 5.7 percent in 12 months through February, underscoring the strength in domestic demand.
Excluding automobiles, gasoline, building materials and food services, retail sales rose 0.1 percent after an upwardly revised 0.8 percent jump in January. These so-called core retail sales, which correspond most closely with the consumer spending component of gross domestic product, were previously reported to have increased 0.4 percent in January.
The government delayed the issuing of tax refunds this year as part of efforts to combat fraud.
"The later-than-usual processing of income tax refunds may have hampered consumer spending. However, the IRS has now caught up to last year's pace, and so spending could get a bump up in March," said Gus Faucher, deputy chief economist at PNC Financial in Pittsburgh.
Tightening labor market conditions, which are steadily lifting wages, continue to underpin consumer spending. Even with retail sales softening in February, domestic demand remains strong enough to generate more inflation in the economy.
In a separate report, the Labor Department said its Consumer Price Index ticked up 0.1 percent last month as a drop in gasoline prices offset increases in the cost of food and rental accommodation. That was the weakest reading in the CPI since July and followed a 0.6 percent jump in January.
In the 12 months through February, the CPI accelerated 2.7 percent, the biggest year-on-year gain since March 2012. The CPI rose 2.5 percent in the year to January. Inflation is firming in part as the 2015 drop, which was driven by lower oil prices, fades from the calculation.
The so-called core CPI, which strips out food and energy costs, increased 0.2 percent last month as new motor vehicle prices fell and apparel prices moderated after spiking in January. The core CPI increased 0.3 percent in January.
In the 12 months through February, the core CPI increased 2.2 percent after advancing 2.3 percent in January. It was the 15th straight month the year-on-year core CPI remained in the 2.1 percent to 2.3 percent range.
The Fed has a 2 percent inflation target and tracks an inflation measure which is currently at 1.7 percent. The U.S. central bank raised its overnight benchmark interest rate by 25 basis points to a range of 0.75 percent to 1.00 percent.
The Fed's policy-setting committee, however, did not flag any plan to accelerate the pace of monetary tightening this year, with officials sticking to their outlook for two more rate hikes. The Fed lifted rates once in 2016.
The dollar fell to a two-week low against a basket of currencies, while prices for U.S. Treasuries rallied. Stocks on Wall Street rose to session highs.
February's retail sales added to January's weak reports on trade, construction and business spending in suggesting sluggish economic growth in the first quarter. The Atlanta Fed is forecasting GDP rising at a 0.9 percent annualized rate in the first quarter.
With the labor market near full employment, slowing growth probably understates the health of the economy and GDP tends to be weaker in the first quarter because of calculation issues that the government has acknowledged and is working to resolve.
In February, motor vehicle sales fell 0.2 percent and receipts at service stations slipped 0.6 percent, reflecting lower gasoline prices. Americans also cut back on dining out and spent less on hobbies and sporting goods.
Sales at electronics and appliances recorded their biggest decline since December 2011. Sales at clothing stores saw their largest drop in nearly a year. Retailers including J.C. Penney Co Inc, Abercrombie & Fitch and Macy's Inc are scaling back on brick-and-mortar operations amid increased competition from online retailers, led by Amazon.com.
Online retail sales jumped 1.2 percent last month. Receipts at building material stores increased 1.8 percent.
Reporting by Lucia Mutikani; Editing by Andrea Ricci