A new travel ban by President Donald Trump could bar people from Afghanistan and Pakistan from entering the U.S. as soon as next week based on a government review of countries' security and vetting risks, three sources familiar with the matter said.

The three sources, who requested anonymity, said other countries could also be on the list but did not know which ones.

A senior Pakistani official confessed on Saturday to helping manipulate results in the country’s elections — a startling claim strengthening a sense that the vote was among the least credible in Pakistan’s history, and deepening the turmoil that has seized the country ever since people went to the polls this month.

At least 28 people were killed on Wednesday by two separate bomb blasts outside the offices of election candidates in southwestern Pakistan, on the eve of a national vote marred by violence and allegations of poll rigging.

More than half a million security officers were deploying ahead of Thursday’s election, with authorities distributing ballot papers to more than 90,000 polling stations.

There have been multiple security incidents in the run-up to the vote, with at least two candidates shot dead and dozens more targeted in attacks across the country.

Two bombs in Pakistan’s southwestern province of Balochistan have killed at least 28 people, officials said, with dozens more injured.

The twin blasts on Wednesday came a day before elections. The attacks targeted the election offices of political parties in the restive region.

The first blast, which killed 16 people, took place at the office of independent election candidate Asfandyar Khan Kakar in Pishin district near the border with Afghanistan, said Jan Achakzai, Balochistan’s caretaker information minister. More than 20 people were reported wounded.

Terrorists attacked two campaign offices in Pakistan’s restive western Balochistan province on Wednesday, a day before the country’s general election, killing 29 people and wounding 40 others.

Seventeen people died and 30 were wounded in the first attack, which took place shortly after noon local time when a suicide bomber struck the campaign office of Asfandyar Khan Kakar, a former minister and independent candidate for the provincial assembly constituency of Pishin, a district close to Pakistan’s border with Afghanistan.

Pakistan’s former prime minister Imran Khan has been sentenced to 10 years in prison for leaking state secrets, his political party Pakistan Tehreek-e-Insaf (PTI) said in a statement Tuesday.

“Former prime minister Imran Khan and former foreign minister Shah Mehmood Qureshi have been sentenced 10 years each in a sham case with no access to media or public in Cypher Case,” PTI said.

It added that their legal team “will challenge the decision in a higher court” as they hope to get the sentence suspended.

Iran and Pakistan traded missile attacks over the past week, supposedly as part of each nation’s efforts to disrupt violence by ethnic separatist groups. The strikes arrived against a backdrop of spiraling conflict in the Middle East, meaning any further violence could risk expanding that fighting.

An Iranian strike on Pakistan this week that drew a rapid military riposte and raised fears of greater regional turmoil was driven by Iran's efforts to reinforce its internal security rather than its ambitions for the Middle East, according to three Iranian officials, one Iranian insider and an analyst.

Both the heavily-armed neighbours, oftentimes at odds over instability on their frontier, appear to want to try to contain the strains resulting from the highest-profile cross-border intrusions in recent years, two analysts and two of the officials said.