WASHINGTON — Just days before the presidential election, U.S. officials are striking back at allegations they failed to respond quickly or efficiently against the deadly attack on the U.S. Consulate in Benghazi, Libya, detailing for the first time a broad CIA rescue effort.

Senior U.S. intelligence officials said Thursday that CIA security officers went to the aid of State Department staff less than 25 minutes after they got the first call for help from the consulate, which was less than a mile from a CIA annex. The detailed timeline provides the first in-depth look at how deeply the CIA was involved in the rescue attempt, and it comes amid persistent questions about whether the Obama administration responded as quickly and effectively as it could to the siege.

The attack on the 11th anniversary of 9/11 by what is now suspected to be a group of al-Qaida-linked militants killed U.S. Ambassador Chris Stevens and three other Americans.