Two men, a doctor and a soldier, have been shot dead in fresh violence in Pakistan's volatile city of Karachi.
The killings bring to 16 the number of people who have died in such shootings in the southern port city since 1 June.
Officials say more than 30 people were killed in violence between rival ethnic groups in the city in May.
Most of those killed belong to the Shia sect, while the remaining are Sunni activists.
The two men killed in Thursday's attacks appeared to have been targeted because they were Shias.
The city's main Shia organisation announced that it will hold protest rallies against the killings on Friday, despite a ban by the government.
Karachi, which has escaped extremist attacks in recent years, has seen an increase in violence since a bomber killed 40 people in a Shia procession in December 2009.
"The murder of Dr Zahid Hussain definitely appears to be a target killing," Police Superintendent Zafar Iqbal told the BBC on Thursday.
He said the doctor had been shot dead as he left his clinic in Karachi's Landhi suburb.
In an earlier attack, a paramilitary soldier of the Pakistan Rangers was gunned down in the city's central district of Garden.
Police officials say he was shot several times in the head and chest.
Meanwhile, the Majlis Wahdat Muslimeen organisation will hold protest rallies in the city on Friday.
Deadly militant group
"The government has failed to protect our community in Karachi,' Maulana Hasan Zafar Naqvi said at a press conference on Thursday.
"The security agencies have failed in their duties. It appears that Karachi is being ruled by a banned organisation."
He was referring to the Ahle Sunnat Wal Jamaat group, formerly known as Sipah-e-Sahaba Pakistan (SSP).
The SSP is an Islamic extremist organisation whose goal is to convert Pakistan into a "pure" Sunni state.
The killings are believed to have been carried out by the Lashkar-e-Jhangvi, a splinter group of the SSP.
The Lashkar-e-Jhangvi is Pakistan's deadliest militant group and is believed to be behind such high-profile attacks as former Prime Minister Benazir Bhutto's assassination.
However, the SSP denies any links to the Lashkar.
"We do not believe in the politics of the bullets, but those of arguments based on facts," Ahsan Farooqi, spokesman for the group in Karachi, told the BBC.
"The reason why we parted with the Lashkar was because they had taken up guns. We also abide by the laws of Pakistan."
However, Mr. Farooqi conceded that many SSP members continued to join the Lashkar.
"What can you expect if the Shia community continues to insult our ideals and the security agencies torture our activists?
"They are practically forced into the arms of the Lashkar."
However, the Shia leadership continues to maintain that the SSP is itself directly involved in the violence.
It has said it will continue with the protests until the government brings the situation under control.