That could give hard-line Islamic candidates and Taliban supporters an advantage as they're able to stump for votes and hold large public rallies that are a traditional hallmark of elections in the country but are extremely vulnerable to attacks.
One of the most serious attacks occurred Tuesday, when a suicide bomber blew himself up outside a meeting of the secular Awami National Party in the northwestern city of Peshawar, killing 16 people.
As he was being treated at the hospital, the uncle vowed that he and other party candidates would not withdraw from the election despite the death threats. With his trousers soaked in blood, he walked among the hospital beds to comfort crying victims and told them, "We are fighting a war for Pakistan's survival."
Hours earlier, a candidate from one of the Islamic parties, Jamiat Ulema-e-Islam, campaigned freely in his constituency in a different part of Peshawar, the capital of Khyber Pakhtunkhwa province.
"There is a difference between the Taliban and terrorists," said Jan.
Faced with the Taliban threat, parties have had to get more creative in their campaigning for the May 11 vote. Members of the Awami National Party and other secular political parties specifically targeted by the Pakistani Taliban have stepped up their use of Facebook and Twitter as well as phone calls and advertisements.
Analysts and secular party candidates fear that the danger could skew election results in favor of hard-line Islamic parties and others who refuse to speak out strongly against the Taliban. Their candidates are able to campaign with much less fear of being attacked, and the concern is this could lead to national and provincial governments inclined to take a softer position toward the militants.
"If you tie my hands, and you want me to fight, I can't," said Mian Iftikhar Hussain, a candidate from the Awami National Party, sitting in his heavily guarded office in Peshawar.
Hussain is running for a provincial assembly seat in the town of Pabbi, which is only 20 kilometers (12 miles) from Peshawar, but it is too dangerous for him to campaign there in person. To get around the danger, Hussain produced a short documentary that highlights development work he has brought to Pabbi and chronicles the sad loss of his only son, who was gunned down by Taliban militants in 2010.
The documentary shows Hussain standing in prayer over the freshly dug grave of his son as a heartfelt poem he wrote in the young man's memory is sung out in mournful tones: "I never knew the enemy could reach my home, my heart, my love would disappear in a grave." He distributes it on DVDs to voters in Pabbi and plans to show the short film there using a couple of big projectors.
Hussain was attacked himself by a suicide bomber at his son's funeral in Pabbi. He survived, but seven other people were killed, including two of his close relatives.
The politician's eyes teared up as he watched the images of his son's grave in the documentary. The film asks his constituents to "vote for those who are sacrificing their lives to save you and your children from terrorists."
It's not only the top Islamic parties like Jamiat Ulema-e-Islam and Jamaat-e-Islami that seem to have been spared by the Taliban in the run-up to the election, but also mainstream parties perceived to take a softer stance on militancy, such as the Pakistan Muslim League-N, which is favored to come out on top in the election, and Pakistan Tehreek-e-Insaf, which is headed by former cricket star Imran Khan. They have all safely held public rallies attended by thousands of people in recent weeks.
These parties have all pushed for peace negotiations with the Taliban instead of military offensives, and the militant group recently said talks should be mediated by the leaders of the top two Islamic parties and the Pakistan Muslim League-N. The parties that have been targeted by the Taliban have also called for peace negotiations, but have demanded the militants put down their weapons and endorse the constitution first and have vowed to continue fighting them until that happens. The Taliban have rejected these conditions.
"This is not a level playing field," Awami National Party leader Afrasiab Khattak said.
The Pakistani Taliban have been waging a bloody insurgency in Pakistan for years to enforce Islamic law in the country and to break the government's alliance with the United States in fighting militants. They have killed thousands of civilians and security personnel in scores of gun and bomb attacks.
The group's main sanctuaries are in the rugged northwest along the Afghan border, including the semiautonomous tribal region and Khyber Pakhtunkhwa. The Taliban have also established a significant presence in the southern city of Karachi and have stepped up attacks there.
The militant group issued audio and video messages last month warning people to stay away from rallies held by the Awami National Party and two other secular parties that have supported army offensives against the militants in the northwest: the Pakistan People's Party, which led the most recent government, and the Muttahida Qaumi Movement, which controls Karachi.
The Taliban have carried out at least 10 attacks against candidates and party workers, mainly those in the Awami National Party. The attacks have killed at least 18 people, including a candidate for the Muttahida Qaumi Movement. Many other candidates have been wounded, including five from the Awami National Party.
"This is a clear attempt by the so-called 'non-state actors' to oust and defeat moderate parties," said Raza Rumi, a political analyst who runs the Jinnah Institute think tank in Islamabad. "This can't be a fair and free election."
The Awami National Party has closed over 50 of its election offices in recent months, mainly in Karachi and Peshawar, because of the threat of attack. The Muttahida Qaumi Movement has stopped holding the massive public rallies that it is known for in Karachi. The Pakistan People's Party had to cancel a large event in southern Sindh province at the beginning of April that was meant to mark the start of its campaign because of security reasons.
Khattak, the Awami National Party leader, called on all political parties to come forward and condemn the attacks on candidates. Many have remained silent or have refused to name the Pakistani Taliban, either for ideological reasons or out of fear of being targeted themselves.
"You have to decide whether you are with the terrorists or with the people," Khattak said.
Associated Press writer Riaz Khan contributed to this report.