Reuters, AFP-JIJI, Washington :A computer network used by Democratic presidential nominee Hillary Clinton’s campaign was hacked as part of a broad cyberattack on Democratic organizations, people familiar with the matter said.The latest attack, which was disclosed Friday, follows reports of two other hacks on the Democratic National Committee (DNC) and the party’s fundraising committee for candidates for the House of Representatives.A Clinton campaign spokesman said a data analysis program that is maintained by the DNC and used by the campaign and a number of other entities “was accessed as part of the DNC hack.””Our campaign computer system has been under review by outside cybersecurity experts. To date, they have found no evidence that our internal systems have been compromised,” said Clinton campaign spokesman Nick Merrill in a statement. A campaign official later said the hackers had access to the analytics program’s server for five days. The program is one of many systems that the campaign accesses to conduct voter analysis, and it does not include Social Security or credit card numbers. The Department of Justice’s national security division is investigating whether cyberattacks on Democratic political organizations threatens U.S. security, sources said Friday.The involvement of the national security division is a sign that the Obama administration has concluded that the hacking was sponsored by a foreign nation, people with knowledge of the investigation said.While it is unclear exactly what material the hackers may have gained access to, the third such attack on sensitive Democratic targets has caused alarm just over three months before the Nov. 8 presidential election. Hackers, whom U.S. intelligence officials have concluded were Russian, gained access to the entire network of the fundraising Democratic Congressional Campaign Committee (DCCC), said people familiar with the matter, detailing the extent of the breach for the first time. Cybersecurity experts and U.S. officials said earlier in the week that they had concluded, based on analysis of malware and other aspects of the DNC hack, that Russia engineered the release of hacked Democratic Party emails to influence the election. The new disclosure that hackers entered the full DCCC network means they would have had access to everything on the network from emails to strategy memos and opposition research prepared to support Democratic candidates in campaigns for the House.The hack of the DCCC, which is based in Washington, was reported first by Reuters on Thursday, ahead of Clinton’s speech in Philadelphia accepting the Democratic Party’s nomination.Several U.S. officials said the Obama administration has avoided publicly attributing the attacks to Russia, as that might undermine Secretary of State John Kerry’s effort to win Russian cooperation in the war against the Islamic State group in Syria.The officials said the administration fears Russian President Vladimir Putin might respond to a public move by escalating cyberattacks on U.S. targets, increasing military harassment of U.S. and allied aircraft and warships in the Baltic and Black seas, and making more aggressive moves in Eastern Europe.Some officials question that approach, arguing that responding forcefully would be more effective than remaining silent. The Obama administration announced in an April 2015 executive order that it could apply economic sanctions in response to cyberattacks.After emails were leaked from the DNC hack, Republican presidential nominee Donald Trump on Wednesday invited Russia to dig up thousands of “missing” emails from Clinton’s time at the State Department, prompting Democrats to accuse him of urging foreigners to spy on Americans.Both candidates were on the road Friday, taking their fight to battleground states at opposite ends of the country. Clinton followed her historic acceptance speech on Thursday as the first female presidential nominee for a major party with a rally in Philadelphia before embarking on a bus tour of the Rust Belt states Pennsylvania and Ohio.In Colorado, Trump promised “no more Mr. Nice Guy.” He trashed Clinton’s speech as “average,” called her a liar and promised to end the immigration of Syrian refugees.