SRINAGAR, Kashmir — India’s governing party ended an alliance with a powerful regional party in the northern state of Jammu and Kashmir on Tuesday, leading to the resignation of a top official and plunging the disputed mountainous territory into fresh turmoil over its leadership.

Ram Madhav, the general secretary of the governing party, the Hindu-nationalist Bharatiya Janata Party, said that it was severing a three-year alliance with the top political group in Kashmir, the Muslim-majority Peoples Democratic Party.

“Terrorism, violence and radicalization have risen, and the fundamental rights of the citizens are under danger in the Kashmir Valley,” Mr. Madhav told reporters in New Delhi on Tuesday, adding that the alliance had not helped to curb a deteriorating security situation in Kashmir. He said power in the area would be passed to the state’s governor.

Shortly after the announcement, Mehbooba Mufti, the top official in Jammu and Kashmir and the head of the Peoples Democratic Party, resigned from her post as chief minister.