Pakistan’s air force launched retaliatory airstrikes against Iran Thursday morning with the aim of taking out militant hideouts, in an attack that killed at least seven persons and sent tensions between the neighboring nations soaring.

The strikes in Iran’s Sistan and Baluchestan province followed Tuesday’s Iranian attack on Pakistan that killed two children in the southwestern Baluchistan province. The attacks Tuesday and Thursday appeared to target separate Baluch militant groups that the two countries say find safe havens in the other. Earlier in the week, Iran also attacked sites in its old foe, Iraq.