"The Secretary-General underlines that all security concerns between the two countries must be addressed by peaceful means, through dialogue and cooperation, in accordance with the principles of sovereignty, territorial integrity, and good neighborly relations," U.N. spokesperson Stephane Dujarric said.

Pakistan launched strikes on separatist militants inside Iran on Thursday, in a retaliatory attack two days after Tehran said it struck the bases of another group within Pakistani territory.

(Reporting by Michelle Nichols; Editing by Doina Chiacu)