Demonstrators carry a banner through Grand Central Station during a protest against police violence towards minorities in New York January 15, 2015. [Photo/Agencies]

NEW YORK - Scores of airport workers rallied on Thursday in New York and other cities to demand higher wages in one of several protests planned by an array of interest groups to mark the birthday of civil rights leader Martin Luther King, Jr.

Other groups are also marking the birthday of King, who is celebrated for advocating peaceful civil disobedience to advance civil rights and who was killed by an assassin in 1968.

Later on Thursday, a rally is planned for outside New York City's police headquarters and at Grand Central Terminal by protesters angered by several recent killings of unarmed black men by white police officers during controversial encounters.

Earlier, about 29 protesters were arrested in Massachusetts after they stopped traffic on a highway into Boston during the morning rush hour, officials said.

About 200 service workers blocked a dozen or so bus and car drivers by sitting down on a street bridge leading to New York's LaGuardia Airport. After a few minutes, an organizer urged the crowd to move on because the police said they would be arrested, and the rally dispersed soon after.