Completely irresponsible move by Iran to fire ballistic missiles at a friendly brotherly nation, with Iran having Arabs, Israelis, and west as enemies, what benefit will it do to have Pakistan as an enemy? Killing of innocent children in balochistan will not benefit Iran. The Iranian members should think about this, if Iran can fire missiles then so can Pakistan, it will not benefit both nations.
Regarding if the attack is on militant houses or on innocent people, Pakistan is claiming Iran targetted civilian houses whilst Iran is claiming they've were militant house, some reports are claiming the anti Iran militant organisation is also confirming their houses have been targeted. That will need to be investigated.
Pakistan should definitely recall ambassador from Iran, pressurise Iran to admit their mistake and apologise and any future missile attacks on Pakistan land will be met with grave consequences. Keep in mind, Pakistan has issues with Afghanistan, enmity with India so we don't need another hostile border. Pakistan will suffer alot, despite people acting all nationalist, a war with Iran will bring consequences to Pakistan aswell, we don't need to please the Americans, Israelis or the Arabs.
Solution:
Iran has been requesting Pakistan for many decades to form a joint border security force to target militants inside both territories, up to 100km. For some reason this has never materialised from the Pakistani side? Both nations should realise, forming a joint force will benefit both nations, peaceful border is a must. A 20,000 joint security force will sort this problem out, destroy all anti Pakistan militants and anti Iranian militants. Pakistan is blamed by India, Afghanistan and even China at times for not targeting militants inside their territories, something for Pakistanis to think about, many PDF members are claiming Pakistan ISI, army is close to USA, and we all know they're under the thumb of Saudis and Uae, what guarantees can you give that Pakistan is not turning blind eye to militants which harm Iran, we all know Raymond Davis, who was cia agent, he was in contacts with many militant organisations, once he was exposed, Pakistan ISI saved him and allowed him to leave the country. Has anyone ever asked the rulers why was cia agent in contact with religious militant organisations? Has that ever been investigated?
Lastly Pakistani and Iranian leadership need to secure their own borders, make sure no militant are able to come inside your territory, same way Pakistan should secure their border with Afghanistan and not point fingers at Taliban when terrorist attacks take place, our PDF members encouraged Pakistan army to strike Afghanistan but now are claiming Iran cannot do the same. Stick to one policy and not double standards.