MANILA—Senator Imee Marcos challenged her brother, President Ferdinand “Bongbong” Marcos Jr., to undergo a hair follicle drug test to respond to her allegations that he, the First Lady, and some of the President’s associates use illegal drugs.

The senator made the remarks after her nephew, House Majority Leader Ferdinand Alexander “Sandro” Marcos, denied her allegations, calling her action “not a conduct of a true sibling.”

“Gustong paingayin ni Sandro ang usap-usapang hindi ako tunay na kapatid. Isa lamang ang solusyon: Magpapa-DNA test ako, magpa-hair follicle test sila,” Imee said on a Facebook post.

In a report, Presidential Communications Office chief Secretary Dave Gomez dismissed the call as a rehash. “Sabi ko nga lumang tugtugin na ito. Mas maraming importanteng bagay ang dapat tutukan ng ating Pangulo at ng ating pamahalaan, ng Kongreso, ng Senado, at ng executive department,” he said.

Imee Marcos made the allegations during a rally of the Iglesia Ni Cristo at the Quirino Grandstand on Monday evening.

Malacañang rejected the accusations, calling them a “desperate move.” “This is definitely a desperate move. Ang pinag-uusapan sa peace rally ay patungkol sa di umanong korapsyon. Ano ang dahilan ni Senator Imee na ang sariing kapatid ay siraan niya?” said Palace Press Secretary Claire Castro.