Locked in a fierce battle in the smartphone market, South Korean giant Samsung on Thursday unveils its latest device aimed at challenging Apple in its home market.

The Galaxy S4 set to be unveiled at New York's Radio City Music Hall has been generating buzz worthy of the iPhone, as the two firms fight for leadership in smartphones in the US and global markets.

Samsung has released no details about the device, but it is widely expected to be an upgraded, slightly larger version of its Galaxy S3, with some new bells and whistles.

According to The New York Times and some other media, the S4 will be able to respond to eye movements with an enhanced interface, and will offer an improved display.

Samsung has released a series of videos on the Internet and has hired dancers to promote Thursday's event with street performances in Times Square, complete with a sign that reads, "Be Ready 4 The Next Galaxy."

Samsung has become the top smartphone maker worldwide with a 29 percent market share, according to IDC, while in the US market Apple remains the king and sells more than one of every three mobile phones.

The Galaxy S3 has sold more than 40 million worldwide since its launch last May and has some analysts debating which of the two firms is ahead in innovation.

Apple, which is known for keeping its plans private, is believed to be working on its own upgrades, including a new version of the iconic iPhone. But Apple shares have slumped some 40 percent from highs hit last year.

Analysts at CIMB, an Asian financial firm, see sales of the Galaxy S4 likely to reach at least 70 million and "even over 100 million is possible." Morgan Stanley said the new device should deliver "solid" results for Samsung.

"Samsung could be the new Apple," said a research note from analysts at Bank of America-Merrill Lynch.

"Apple's recent products, the iPhone 5 and the iPad mini simply can't stand next to the innovation and buzz Samsung has brought to the market."

The two firms are also battling in the market for tablet computers -- with Apple leading the market but losing some market share -- and have been in a bitter court battle over patent infringement in US courts and elsewhere,

A judge recently cut $450 million from a $1 billion award to be paid by Samsung in a major case in California, saying a jury had wrongly calculated the damages.

Apple had accused its rival of massive and willful copying of its designs and technology for smartphones and tablets.

Some analysts say the legal struggle will have little impact on the market because new products hit the market by the time the cases can be resolved in the courts.