Apple vs. Samsung: Who's the king of the smartphones?

In this corner Apple; in that corner Samsung. Who's the smartphone champ?

Apple is still the dominant smartphone maker, at least in the U.S., according to stats out today from NPD Group. The research firm pegged Apple's U.S. market share at 29 percent for the first quarter, up 7 percent from a year ago.

At the same time, Samsung's share shot up by 140 percent. But at 24 percent of the U.S. market, it still trailed that of Apple last quarter.

Apple's iPhone commanded the top three spots in market share among devices for the quarter, with the iPhone 4s in first place, followed by the iPhone 4 and the iPhone 3GS. Samsung's Galaxy S II took home fourth place, with HTC's Evo 3D in fifth.

Apple continued to dominate despite a decline in share from the holiday quarter, according to NPD.

"After some release of pent-up demand from customers adopting the iPhone 4S, coupled with the company's strength in the holiday season, Apple's share fell in the first quarter, as we've often see it do in the quarter following its introduction of a new handset," Ross Rubin, executive director for NPD's Connected Intelligence, said in a statement. "Now that the iPhone is available on Sprint, though, the increased carrier coverage has created a higher baseline for Apple's share than we have seen in the past."

Samsung led the way among Android vendors, thanks in part to strong demand by prepaying customers. Android phones grabbed 79 percent of the prepaid smartphone market last quarter, while 38 percent of all prepaid phones in the U.S. were made by Samsung alone.

"Samsung is the only market leader from the feature phone era to transition to market leadership in the smartphone era in the U.S.," Rubin said. "Its broad carrier support and advertising -- particularly in the ascendant prepaid segment -- have helped it achieve the highest market share among Android handset providers in the U.S."

Though Apple may have beaten Samsung in the U.S. smartphone wars last quarter, the iPhone maker is still trailing its rival around the world.

During the first quarter, Samsung grabbed a leading global market share of 29.1 percent, according to IDC. That surpassed Apple's share of 24.2 percent. Samsung was also crowned the top dog over Apple by Juniper Research, which said yesterday that Samsung shipped 11.8 million more smartphones than did Apple, giving it a firm lead.

The latest quarterly win for Samsung follows Apple narrowly capturing the top smartphone spot around the world during the fourth quarter, according to IDC.

Apple and Samsung have been playing a game of tag in the smartphone arena over the past year.

Apple has continued to see heavy demand for its iPhone, but Samsung's market share has skyrocketed both globally and in the U.S.

Among mobile operating systems, Android grabbed even more ground against Apple's iOS last quarter, according to NPD. Android phones captured 61 percent of the U.S. market, up 24 percent from the prior quarter. At the same time, Apple's iOS share dropped to 29 percent from 41 percent in last year's final quarter.