Further Pence said that "minimum" chlorine was used in the attack along with serin.
At the same time, he warned that the US was prepared to "sustain this effort if necessary", though he expressed hopes that the combination of strikes and condemnation from countries like Canada would see Syria abandon such weapons.
There "will be a price to pay" if Syria ever uses chemical weapons again, as the United States is ready to take additional action, Pence told reporters travelling with him to Peru to attend the Summit of the Americas.
Pence was in Lima on behalf of U.S. President Donald Trump, who opted to stay home to oversee Friday's military strikes against Syria.
US Vice President Mike Pence has threatened that Washington is set to respond to possible retaliatory moves against its missile attacks on Syria, by Damascus or its allies, specifically Russian Federation and Iran.
The discussions on the sidelines of the Summit of the Americas in Peru came as U.S. officials said they believed they were narrowing differences over a revised North American Free Trade Agreement, 24 years after its inception.
Axios reported Sunday that Trump was upset when he learned Pence was hiring Jon Lerner to advise him on national security and foreign policy.
During his meeting with Pence, Pena Nieto urged for the relationship between Mexico and the U.S. to be based on "mutual respect".
Pence said he was grateful for the opportunity to meet with the Mexican president, although he made no reference to Pena Nieto's call for "mutual respect". "We are very close to the kind of breakthrough on issues of immigration, drug interjection" that will be of benefit to both sides, Pence said.
NDP leader Jagmeet Singh issued a statement Saturday saying "escalating violence through further military action is not the way to bring peace and stability to Syria and the surrounding region", and calling for more funds to investigate atrocities in Syria. Pence then attended a banquet hosted by Peruvian President Martin Vizcarra.