The brother objected to love matches and wanted the women to marry someone within extended family.
In a latest case of 'dishonour killing', a man allegedly murdered his two sisters on the eve of their weddings in Pakistan's Punjab province police said today.
Kosar and Gulzar Bibi, aged 22 and 28, were shot dead by their 35-year-old brother Nasir Hussain on Friday as they prepared to marry men they had chosen themselves, senior police officer Mehar Riaz told Agence France-Presse.
Hussain objected to the love matches and had wanted the women to marry someone within the extended family, he added.
"The brother shot dead both the sisters yesterday and fled the site," the officer said, adding that a search was underway.
"It is a simple case of killing for honour," he said.
Father of the family Atta Mohammad told reporters that Hussain had "destroyed everything".
"He ruined my family, he destroyed us, he destroyed everything" Mohammad said.
The murders came days after social media starlet Qandeel Baloch was strangled to death by her brother who said he was "not embarrassed" to have killed her, reigniting calls for action against the crime.
Hundreds of women are murdered by relatives in the conservative Muslim nation each year on the pretext of defending what is seen as family honour.
Pakistan's law minister this month announced that bills aimed at tackling "honour killings" and boosting rape convictions would soon be voted on by parliament, after mounting pressure to tackle a pattern of crime that claims around 1,000 lives a year.
The perpetrators of so-called honour killings -- in which the victim, normally a woman, is killed by a relative -- often walk free because they can seek forgiveness for the crime from another family member.