SAN JUAN – Puerto Rico’s police chief, Jose Figueroa Sancha, resigned Saturday after a monthly record of 101 murders were committed in the U.S. commonwealth in June.

Col. Jose Luis Rivera will take over on an interim basis, according to an official statement by Gov. Luis Fortuño’s administration, which said Figueroa Sancha asked to be relieved of his duties to attend to unspecified health problems.

“Jose Figueroa Sancha was an incorruptible, tireless and implacable fighter against crime and drug trafficking. Under his command, powerful drug-trafficking organizations were attacked and dismantled like never before in Puerto Rico,” the governor said in the statement.

The Puerto Rican press reported Saturday that the decision may have been prompted by a spiraling homicide rate on the island, where an average of 10 people are killed every weekend.

Last month’s homicide figure was 19 more than in June 2010 and 21 more than in June 2009, while the total number of murders this year has climbed to 568, according to the Puerto Rican Police Department’s Office of the Auxiliary Superintendent of Strategic Operations.

The record-high murder toll in June was due in large part to 25 homicides last weekend, including the deaths of four people in a settling of scores among drug dealers.

The part of the island with the highest number of homicides last month was the San Juan district of Santurce.

Authorities say violence on the island is mainly attributable to rival drug gangs’ battles over points of sale.

Fortuño’s administration has stepped up the number of police officers on the streets and even deployed the National Guard to halt the drug violence, but the strategy has not put a dent in the killings.