MANILA, Philippines — A Philippine town mayor who was linked by the president to illegal drugs was fatally shot in his office Wednesday in the latest brazen attack on local officials.

Four gunmen barged into the Ronda municipality's town hall in Cebu province early Wednesday and repeatedly shot Mayor Mariano Blanco, who was sleeping in his office, police said. The men fled in a van.

A police report said the gunmen ordered two watchmen to lie on the ground at gunpoint, rushed to the town hall, and then "a burst of gunfire was heard from the mayor's office." The watchmen later found Blanco dead and notified the police.

President Rodrigo Duterte had included Blanco in a list of officials allegedly linked to illegal drugs. The mayor had denied any wrongdoing and had been alternately sleeping in his office and his nearby house after reportedly receiving death threats, officials said.

Last year, Blanco was stripped of control over the local police due to his alleged links to illegal drugs. Blanco's nephew, Ronda Vice Mayor and lawyer Jonah John Ungab, was shot and killed in his car by motorcycle-riding men in February after attending a court hearing for a client, a suspected drug lord, in central Cebu city.

Investigators were trying to determine whether Blanco's killing was related to a local political rivalry, a personal feud or his alleged links to the drug trade, police said, without elaborating.

Attacks on local officials by motorcycle- and car-riding assassins have continued despite concerns raised by a national association of town and provincial officials which has sought additional security.

In July, Mayor Antonio Halili was fatally shot in the heart while singing the national anthem at a flag-raising ceremony in Tanauan city, south of Manila, in an assault by gunman positioned on a nearby hill. The shooting was captured on cellphone videos which were posted online, prompting police to order tighter security.

The next day, the mayor of northern General Tinio town was killed in an SUV by motorcycle-riding assassins.

The killers of both mayors, among several who have been slain under Duterte, remain at large.

The killings have taken place alongside a national anti-drug crackdown ordered by Duterte that has left more than 4,500 mostly poor drug suspects dead in the last two years. Duterte has denied condoning extrajudicial killings but has openly threatened drug suspects, including officials and policemen involved in the drug trade, with death.