ISLAMABAD, Pakistan — Pakistan’s independent Human Rights Commission warned Monday that ‘‘blatant, aggressive, and unabashed’’ attempts have been made to manipulate the results of national elections set for later this month.

A prominent activist, I.A. Rehman, called it ‘‘the dirtiest election’’ in the country’s troubled history of trying to maintain democratic rule.

The Human Rights Commission of Pakistan issued a statement raising several warning flags, including allegations that members of disgraced former prime minister Nawaz Sharif’s Pakistan Muslim League party were ‘‘being pressured to switch political loyalties,’’ while some of Sharif’s candidates were being asked to step down.

In jail since his return to Pakistan last week, Sharif is serving a 10-year sentence on corruption charges. On Monday, Sharif appealed the conviction as did his daughter, Maryam, and his son-in-law, who received seven- and one-year sentences respectively also on charges of corruption over the family’s purchase of luxury apartments in London.

If the judge grants the appeal, Sharif could be released on bail.

Violence has escalated in advance of the balloting, with horrific attacks over the weekend killing 153 people.

Gunmen on Sunday night opened fire at the election headquarters of the secular Awami National Party in the town of Chaman in Baluchistan, wounding former senator Daud Achakzai who was campaigning for Zumurak Khan, a contender for a seat in the provincial legislature.

On Friday in Baluchistan’s Mastung district, an Islamic State suicide bomber killed Siraj Raisani, a candidate for the provincial assembly, along with 148 others during an election rally.

The Human Rights Commission’s statement questioned a decision by the Election Commission of Pakistan to deploy 350,000 security personnel outside as well as inside polling stations on election day.

Rehman expressed concern that such a deployment could intimidate voters. Instead Human Rights Commission member and cofounder Hina Jilani said security personnel should be deployed to protect campaigns ahead of elections when the dangers are self-evident.

‘‘These [terrorist] forces were supposed to be eliminated, but still they exist and can strike where they want,’’ said Jilani, who is also a member of the Elders, an international non-government organization of public figures known for their work promoting peace and human rights.

The Human Rights Commission said in its statement it “feels strongly that the political space ceded to banned outfits has emboldened militant groups.’’

Sharif’s Pakistan Muslim League party is heading into the race for the 342-seat National Assembly and four provincial parliaments weakened by the scandal surrounding Sharif and an irate military.

Sharif, who has been banned from politics, is believed to have run afoul of the military, which has ruled Pakistan directly or indirectly for most of its 71-year history. He sought to restrict its involvement in civilian affairs and criticized army efforts to combat extremist groups, despite Sharif’s own past courting of religious groups in search of votes.

Rights groups say the military is seeking to influence the election outcome to keep Sharif’s party out of power.

The Human Rights Commission said candidates from Sharif’s party, as well as the left-leaning Pakistan People’s Party and the secular Awami Workers party, ‘‘have reported being harassed by law enforcement and security personnel during their campaign, their movements monitored or restricted without good reason, and their election banners removed without cause.’’

Pakistanis will go to the polls on July 25 to elect 342 members of the lower house of Parliament, the National Assembly, which is the country’s law-making body, and four provincial legislatures.

Members of Sharif’s Muslim League party hope to win a majority of the seats in Parliament and form the next government. His brother, Shahbaz, has taken over the leadership of the party.