"Here officially, we don’t have any specific attribution today in terms of a particular group by name or groups who might be responsible for this," Psaki said. "In terms of intent, it’s also difficult because of that for us to ascribe intent with any real specificity or certainty in these types of attacks. We can’t say definitively who caused them or why the attacks seem to have stepped up."
It is possible that they could be related to JCPOA talks with Iran in Vienna or the anniversary of the assassination of Iranian military leader Qasem Soleimani by a US drone strike, Psaki said.
The Coalition forces have been targeted in a series of attacks in Iraq and Syria, including indirect rocket fire attacks near the Ain al-Asad Airbase in Iraq and Green Village base in Syria.