The attacks were carried out Saturday; one on a bus carrying female university students in Quetta, located in southwestern Pakistan's Baluchistan province, and the other a hospital complex were the wounded in the first attack were taken, The New York Times reported.
Lashkar-e-Jhangvi, a banned terrorist group with links to al-Qaida, claimed responsibility for both attacks.
In the bus attack, at least 14 women were killed and 19 others were injured, the report said. The bus, which was carrying female students from Sardar Bahadur Khan University, was destroyed.
Then, a second blast went off inside the Bolan Medical Complex, where the injured were brought for treatment and local leaders gathered to visit the wounded, the Times said. Shortly after the blast, gunmen forced their way into the hospital and exchange of heavy gunfire with security officers.
It took security forces several hours to regain control of the hospital, officials said.
At least 11 people were killed in the incidents at the hospital, officials said.
Earlier Saturday, militants in another part of the Baluchistan province also destroyed a historic building known as Jinnah's Residency, which was once used by Pakistan's founding leader
The city of Quetta declared an official day of mourning Sunday for those killed in the attacks, which had no clear motive, the BBC reported.
A spokesman for Lashkar-e-Jhangvi told the BBC that the attacks were revenge for a raid against the group carried out by Pakistani security forces that resulted in the deaths of a woman and children.
United Nations Secretary General Ban Ki-moon condemned the attacks in a statement through his spokesperson Saturday.
"[The Secretary-General] deplores the heinous nature of the attacks on a university bus carrying women students and educators and a hospital facility, as well as the heritage Quaid Azam Residency which has a historical importance as a former home of Muhammad Ali Jinnah," the statement said. "No cause can justify such violence."