US stock indices climbed to new heights on Thursday as traders welcomed blockbuster earnings, a soothing message from the Federal Reserve and more data pointing towards a solid economic recovery.

Despite rocky trading during the session, the S&P 500 finished at a new record, while the Dow and Nasdaq also gained as investors overcame earlier hesitation to rally as more companies reported blockbuster earnings.

Government data helped the rally as reports showed the US economy accelerated in the first quarter to an annualized growth rate of 6.4 percent, and that first-time unemployment claims fell to a new pandemic-era low of 553,000 last week.

"The key takeaway from the report is that it is indicative of an economy that is bouncing back sharply with the help of stimulus payments and reopening activity that has been catalyzed by Covid vaccines," analyst Patrick J. O'Hare of Briefing.com said of the GDP report.

"Holding a positive line is what this bull market is known for."

While previous strong data has fanned investor fears of a spike in inflation that could force central banks to step back from their loose monetary policies, the Fed said Wednesday it will stay the course.

Even as the central bank was more upbeat about the outlook for the world's largest economy, Fed chief Jerome Powell strenuously tamped down inflation concerns by saying the expected jump in prices will be temporary, owing to last year's low base of comparison, and is not likely to need policy action.

He added it was not yet time to start talking about tapering its vast bond-buying program that has pumped trillions of dollars into the financial system.

"The second half outlook is up in the air, but for now everyone wants to ride this last big wave of growth," said analyst Edward Moya at currency trading platform Oanda.

The hearty finish for US indices came after they briefly sunk in midday trading, despite Apple and Facebook reporting blowout earnings after markets closed on Wednesday. Apple fell slightly in trading Thursday but Amazon finished sharply higher.

Google also reported strong results this week, underscoring the strength of the tech giants that have thrived as the pandemic accelerated a shift to working, learning, shopping and socializing online.

Lyft and Uber Technologies saw dramatic plunges after the US Labor secretary told Reuters he believes most "gig" workers -- like those employed by the ride-hailing services -- should be classified as employees and eligible for full benefits.

The mood was less exuberant in European markets, where stocks gave up gains to end the day lower.

South Korean giant Samsung also said Thursday its net profit jumped by almost half in the first three months.

Meanwhile, the price of a ton of copper crossed the $10,000 level on Thursday for the first time since February 2011 thanks to strong demand in China and the weak dollar.

The industrial metal is seen as an indicator for the general health of the economy by market analysts, which have dubbed it Dr. Copper.

Joe Biden hailed the US vaccination rollout and recovery from the pandemic, and laid out a new massive spending splurge aimed at helping American families
President Joe Biden laid out a new massive spending splurge aimed at helping American families POOL / Melina Mara

Its price has risen by more than a quarter since the start of the year as the global economy begins to shake off the Covid-19 pandemic.

New York - Dow: UP 0.7 percent at 34,060.36 (close)

New York - S&P 500: UP 0.7 percent at 4,211.47 (close)

New York - Nasdaq: UP 0.2 percent at 14,082.54 (close)

EURO STOXX 50: DOWN 0.5 percent at 3,996.90 (close)

London - FTSE 100: DOWN less than 0.1 percent at 6,961.48 (close)

Frankfurt - DAX 30: DOWN 0.9 percent at 15,154.20 (close)

Paris - CAC 40: DOWN less than 0.1 percent at 6,302.57 (close)

Hong Kong - Hang Seng Index: UP 0.8 percent at 29,303.26 (close)

Shanghai - Composite: UP 0.5 percent at 3,474.90 (close)

Tokyo - Nikkei 225: Closed for a holiday

Euro/dollar: UP at $1.2118 from $1.2091 at 2130 GMT

Pound/dollar: UP at $1.3940 from $1.3913

Euro/pound: UP at 86.91 pence from 86.90 pence

Dollar/yen: UP at 108.92 yen from 108.70 yen

Brent North Sea crude: UP 1.8 percent at $68.51 per barrel

West Texas Intermediate: UP 1.6 percent at $64.91 per barrel