Mr Biden said a political deal "would be better" but "if that's not possible" the US would pursue alternatives.
US officials said Mr Biden's remarks on a deal referred to planned peace talks between Syrian officials and rebels.
They said his comment on possible military action applied only to IS.
The US vice-president was speaking after meeting Turkish PM Ahmet Davutoglu in Istanbul.
Commenting on the chance of achieving a political settlement in Syria, Mr Biden said: "We are neither optimistic or pessimistic. We are determined."
Referring to possible military action, he said this would entail "taking out Daesh", using the Arabic acronym for IS.
Mr Biden said he and Mr Davutoglu had discussed how their countries could further support Sunni Arab rebels opposing Syrian President Bashar al-Assad.
In other comments, Mr Biden said Washington recognised that the Kurdistan Workers Party (PKK), which is banned in Turkey, was as much of a threat to Ankara as IS.
"It is a terror group plain and simple and what they continue to do is absolutely outrageous," he said.
The PKK, which is listed as a terrorist group by Washington and the EU, has been accused of carrying out a number of deadly attacks on Turkish security forces since a truce collapsed in July.
The group, which has been fighting Turkey for an autonomous homeland for the Kurds for decades, has said the truce had "no meaning" after it faced assaults from Turkish forces.
Mr Biden, who also held talks with President Recep Tayyip Erdogan during his visit, on Friday strongly criticised restrictions on freedom of expression in Turkey.
He said that intimidating journalists, shutting down social media and accusing government critics of treason set a poor example to the region.

Garcia, who died in 1995, will be inducted posthumously alongside lyricist Robert Hunter for their work in the legendary psychedelic group.
They will be joined by country artists Toby Keith and Bobby Braddock and blues pioneer Willie Dixon.
The ceremony will take place on 18 June in New York.
Songwriters Hall of Fame president Linda Moran said: "Each one of these brilliant music creators have written instantly recognisable classics, songs that are both of their time and timeless."
Cyndi Lauper became a household name by covering Robert Hazard's Girls Just Wanna Have Fun in the 1980s - but she has also had hits of her own and won a Tony Award in 2013 for best score for the hit Broadway musical Kinky Boots.
Linda Perry was a member of 4 Non Blondes and has written hits for stars including Pink, Gwen Stefani and Alicia Keys. One of her biggest successes was Beautiful, which was a worldwide hit for Christina Aguilera.
Toby Keith has sold more than 40 million albums worldwide, while Braddock is a songwriter who has had a career of more than 40 years and is the only living person to have written number one country hits in five consecutive decades.
His songs have become country music standards, including DIVORCE, recorded by Tammy Wynette.
Willie Dixon, who died in 1992, was one of the most prolific songwriters of all time, he has been called "the poet laureate of the blues".
His most famous compositions include Hoochie Coochie Man, I Just Want to Make Love to You and You Can't Judge a Book by the Cover.
Dixon's songs have been recorded by artists including Bob Dylan, Jimi Hendrix, Led Zeppelin and the Rolling Stones.
The songwriters were chosen from a list that also included Tom Petty, Vince Gill, Elvis Costello and Kenneth Babyface Edmonds.
Linda Moran said: "Our 2015 line-up of inductees represents the rich diversity of American musical styles - rock, country, blues and pop - that have captivated the world over the past six decades."

Jaymie Stuart Hall suffered a number of serious injuries during a disturbance in Dumbryden Gardens, Wester Hailes, at about 21:25 on Saturday.
The 35-year-old was taken to the Royal Infirmary of Edinburgh but died a short time later.
The arrested man is expected to appear at Edinburgh Sheriff Court on Tuesday.
US Vice-President Joe Biden has said the US and Turkey are prepared to seek a military solution against so-called Islamic State (IS) if a political agreement in Syria proves impossible.
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Cyndi Lauper, Linda Perry and the Grateful Dead's Jerry Garcia are to be inducted into the Songwriters Hall of Fame.
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A 41-year-old man has been charged with murder following the death of a man in an Edinburgh street.