HAVANA — Thousands of people ran Sunday in Cuba’s most important international marathon, with some using the race to protest U.S. economic sanctions against the island.

The Marabana marathon, held every November to commemorate the founding of Havana, took runners along city’s iconic streets and landmarks, such as the Paseo del Prado and the Capitol building. Many wore signs expressing solidarity with Cuba.

“Cuba is not a threat; the blockade is,” read the signs that many of the 3,000 participants wore on their backs.

The U.S. embargo against Cuba was first imposed in 1960, after Fidel Castro led a revolution that toppled dictator Fulgencio Batista and nationalized properties belonging to U.S. citizens and corporations. As a result, the Caribbean country has endured decades of economic and financial troubles and is now being pushed to a breaking point after U.S. President Donald Trump announced in late January that he would impose tariffs on any country that sells or provides oil to Cuba.

The warning has effectively cut off fuel to the island, leading to widespread power outages that disrupt water supplies and internet and telephone services.

“The blockade is suffocating the Cuban people,” Yuraldi Cava, a 58-year-old state employee, said while running. “We are going to win this fight.”

Mayté Vigoa, Havana’s provincial government coordinator for sports, said the city had to make a major effort to hold the international race because of the island’s precarious economic conditions. She confirmed that the sportswear brand Adidas, a longtime sponsor of the competition, did not provide support this year.

Other companies with longstanding ties to Cuba, including Meliá Hotels International, said they were withdrawing from the island because of the tightening of sanctions.

Participants included families with children and people with disabilities dressed in sportswear and carrying water bottles as enthusiastic onlookers cheered them on from the sidewalks.

Those protesting the sanctions included foreigners who wore red-and-white sweatshirts with the message “Cuba is not alone.”

The marathon is recognized by the Association of International Marathons and Distance Races, and runners can use their times as official qualifying marks. The event also features a half-marathon, as well as the more popular 10-kilometer and 5-kilometer races.