Gunmen on a motorcycle have killed a prominent women's rights activist in Pakistan just hours after she held a forum on the country's restive Baluchistan region.

Police declined to speculate on a motive for the killing of Sabeen Mahmud but friends and colleagues immediately claimed it was a targeted assassination.

The military and intelligence services still hold tremendous sway despite the re-emergence of democracy in the country.

The gunmen shot both Mahmud and her mother, Mehnaz Mahmud, as they stopped at a traffic light on Friday night in an upmarket Karachi district, senior police officer Zafar Iqbal said. Later, Mahmud's car was brought to a nearby police station; blood stained the car's white exterior, the front driver's side window was smashed and a pair of sandals sat on the floor, surrounded by broken glass.

"Two men riding a motorcycle opened fire on the car," Mr Iqbal said. Ms Mahmud "died on her way to the hospital. Her mother was also wounded," he said.

Alia Chughtai, a close friend of Ms Mahmud, said that she was driving at the time of attack and her mother was sitting next to her. Ms Chughtai said Ms Mahmud's driver, who escaped unharmed, was sitting in the back seat at the time of the attack. She did not know why he wasn't driving the car.

Earlier that night, Ms Mahmud hosted an event at her organisation called The Second Floor to discuss human rights in Baluchistan, an impoverished but resource-rich south-western province bordering Iran.

Thousands of people have disappeared from Baluchistan province in recent years amid a government crackdown on nationalists and insurgent groups there. Activists blame the government and intelligence agencies for the disappearances, something authorities deny.

Qadeer Baluch, an activist who last year led a nearly 3,000-kilometre (1,900-mile) protest march across Pakistan to demand justice for the missing in Baluchistan, attended Mr Mahmud's event on Friday night. Mr Baluch, known widely as Mama or "Uncle" in Urdu, hinted that the government could be involved in Ms Mahmud's slaying.

"Everybody knows who killed her and why," he told Pakistan's The Nation newspaper.

In a statement, Prime Minister Nawaz Sharif condemned the killing and ordered an investigation. The US Embassy in Islamabad also condemned her murder and offered condolences to her loved ones.

Pakistan's powerful army condemned the killing, pledging that the country's intelligence agencies would assist in the investigation.