WASHINGTON, Feb. 6 (Xinhua/ Sun) -- U.S. President Barack Obama on Thursday pledged American commitment to Haiti in its rebuilding process after a devastating earthquake struck the impoverished Caribbean nation four years ago.

Before a meeting with visiting Haitian President Michel Martelly, Obama praised Haiti's post-quake progress for the country's strong leadership and the U.S.-led international support.

The massive quake, which struck Haiti on Jan. 12, 2010, killed some 220,000 people and left 1.5 million others homeless, according to UN figures.

"The economy is growing; security is improving; infrastructure is getting rebuilt... and businesses are starting to return to Haiti," Obama said. "It's been a very slow and difficult process, and I think we are all recognizing that we have a lot more work to do."

Together with Haiti, the U.S. is working to create the conditions for sustainable long-term development and prosperity, White House spokesman Jay Carney told a press briefing Thursday.

"Our relationship with Haiti is broader and deeper than short- term reconstruction alone," Carney said.

Obama also said he was encouraged by steps Haiti has taken to remove "political roadblocks" to holding elections, which are two years overdue.

Martelly thanked Obama for U.S. support to Haiti and said he hoped to discuss with him issues on security, drug trafficking and Haiti's democratic process.