Activists carrying banners in protest of "climate injustice" stormed the field before the start of the third quarter of Saturday's game between Harvard and Yale, causing a lengthy delay and leading police to handcuff and detain several protesters. 

Groups of students from both universities marched toward midfield at the Yale Bowl after the band had finished performing and as players were warming up for the start of the second half. One long banner carried by several students said both Yale and Harvard "are complicit in climate injustice."

Protesters called for the two schools, longtime Ivy League rivals, to divest from fossil fuels and cancel their Puerto Rico debt holdings. Endowment holdings at Harvard and Yale are managed in part by fund managers and private equity firms invested in Puerto Rican debt.

Demonstrators stage a climate change protest at the Yale Bowl delaying the start of the second half between Harvard and Yale.

The number of protesters grew into the hundreds, all within a stretch of space on either side of the large Yale logo at midfield. 

"Hey hey, ho ho, fossil fuels have got to go," chanted protesters.

A public-address announcement asked protesters to leave the field "as a courtesy to the players," and that "as a courtesy to both teams, the game must resume.”

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After about an hour, police formed a line and moved forward, from the Yale sideline toward the Harvard sideline. A protest leader encouraged all “internationals” to leave. An agreement was reached to escort the remainders off, with one police officer to every two protesters.

Those who did not leave then – perhaps one or two dozen – were informed by Yale Police Chief Ronnell Higgins that they would be arrested.

Yale officials said in a statement handed to reporters in the press box during the fourth quarter that the school “stands firmly for the right to free expression.”

“It is regrettable,” a statement attributed to the Ivy League said, “that the orchestrated protest came during a time when fellow students were participating in a collegiate career-defining contest and an annual tradition when thousands gather from around the world to enjoy and celebrate the storied traditions of both football programs and universities.”

Harvard led 15-3 at halftime against the favored Bulldogs, which entered Saturday tied with Dartmouth atop the Ivy League standings and ranked No. 25 in the Football Championship Subdivision. The Crimson then led by 17 points in the fourth quarter before Yale rallied to force overtime. A touchdown in the second extra period gave the Bulldogs the win and a share of the conference title.

The two universities have met 136 times since 1875, with Yale holding a 68-60-8 lead in the series. Only two other rivalries have met more often in the history of college football.

Contributing: The Associated Press