U.S. intelligence officials said that the Russian government appears to have succeeded in penetrating computer systems associated with both parties, but “prioritized” Democratic institutions in a campaign that culminated with the posting of thousands of sensitive emails on the WikiLeaks website.

The CIA briefed the administration that it thinks the Russians “breached” the RNC systems, according to a senior U.S. official, who like others spoke on the condition of anonymity because of the sensitivity of the issue. “Obviously there haven’t been the same sort of leaks and pilfered documents spread about from this intrusion as there were from the various DNC and related incursions.”

Other officials familiar with the CIA’s assessment said there is “high confidence” that the RNC was targeted but less certainty that the Russians got inside the committee and stole material.

The explanation for the lack of damaging Republican leaks remains a source of debate across the U.S. intelligence community, but officials think it may reflect in part an allocation of resources and effort by Russian-backed actors who have been tied to the hacking campaign.