Hillary Rodham Clinton has decided to end herhistoric presidential campaign while leaving her options open toretain her delegates and promote her issue agenda, a campaignofficial says.

The former first lady told House Democrats during a privateconference call Wednesday that she will express support for BarackObama's candidacy and congratulate him for gathering the necessarydelegates to be the party's nominee.

"Senator Clinton will be hosting an event in Washington, D.C.,to thank her supporters and express her support for Senator Obamaand party unity. This event will be held on Saturday to accommodatemore of Senator Clinton's supporters who want to attend," hercommunications director Howard Wolfson said.

Also in the speech, Clinton will urge once-warring Democrats tofocus on the general election and defeating Republican presidentialcandidate John McCain.

The announcement brought to a close an epic five-monthnominating battle pitting the first serious female candidateagainst the most viable black contender ever.

Obama Tuesday night secured the 2,118 delegates to claim theDemocratic nomination, but Clinton stopped short of acknowledgingthat milestone, saying she would.

An adviser said Clinton and her lieutenants had discussedvarious ways a presidential candidacy can end, including suspendingthe campaign to retain control of her convention delegates andsustain her visibility in an effort to promote her signature issueof health care.

The other options include freeing her delegates to back Obamaand ending her candidacy unconditionally. The official stressedthat neither Clinton nor her inner circle had decided specificallywhat course to take other than to recognize that the active stateof her bid to become the nation's first female president had ended.

On the telephone call with impatient congressional supporters,Clinton was urged to draw a close to the contentious campaign, orat least express support for Obama. Her decision to acquiescecaught many in the campaign by surprise and left the campaignscrambling to finalize the logistics and specifics behind hercampaign departure.