The Taliban hinted Thursday that they may launch attacks against foreigners helping Pakistan respond to the worst floods in the country’s history, saying the presence of aid groups was “unacceptable.” The UN said it would not be deterred by violent threats.

The militant group has attacked aid workers in the country before, and an outbreak of violence could complicate a relief effort that has already struggled to reach the 8 million people who are in need of emergency assistance.

Pakistani Taliban spokesman Azam Tariq claimed the United States and other countries that have pledged support are not really focused on providing aid to flood victims but had other motives he did not specify.

He strongly hinted that the militants could resort to violence, saying the foreign presence is “unacceptable” and “when we say something is unacceptable to us, one can draw one’s own conclusion.”

Foreign countries have pledged nearly $800 million and provided aid workers to help Pakistan cope with floods that began almost a month ago with the onset of the monsoon season and have ravaged a massive swath of Pakistan, from the mountainous north to its agricultural heartland.

The U.S. military has also stepped in to help, flying helicopters that have evacuated flood victims and delivered relief supplies in Khyber Pakhtunkhwa, the northwest province that was hit hardest by flooding.

Many aid organizations involved in the relief effort have been in Pakistan for years and use networks of locals in the most dangerous areas.

The Pakistani Taliban have attacked international aid organizations in the country in the past, including the UN’s World Food Program last October and World Vision in March.

Since the floods hit, violence has been relatively low in the country, but three bomb attacks in northwestern Pakistan on Monday killed at least 36 people.

While increased Taliban attacks would complicate the flood relief effort, the group could also risk backlash from the millions of victims who have lost everything and are desperate to receive food and shelter.

The Associated Press contributed to this report.