An Israeli military spokesman said that two Israeli soldiers were wounded in a "cross-border attack from Egypt."
Peter Lerner, Israel Defense Forces spokesman for international media, made the statement on his official Twittter account on Wednesday afternoon.
Lerner said those injured are two infantry members - one man and one woman - from the mixed-sex combat unit Caracal Battalion.
Israeli daily Haaretz said troops have been sent to the scene.
There was no immediate claim of responsibility.
Senior Israeli military officers were convening to assess the situation following the attack, said Avichay Adraee, Israeli army spokesman for Arab media.
He quoted another spokesperson for the Israeli Defence Forces as saying that "the army would not hesitate to respond to any attacks on its soldiers or citizens."
The Egyptian army is battling a simmering Islamist insurrection based in the mountainous peninsula, killing hundreds of extremist fighters since it waged a broad operation to stamp out militancy over a year ago.
Hundreds of Egyptian police and troops have been killed in bombing and shooting attacks since mid-2013.
Militants in the Sinai have occasionally launched cross-border strikes on Israel, but have more recently focused on battling forces at home.
On 15 July, four Israeli civilians were wounded when militant fighters in Sinai launched two rockets at the southern Israeli resort of Eilat.
In January, Ansar Bayt al-Maqdis, Egypt's most active militant group, claimed responsibility for a rocket attack on Eilat, which caused no casualties.
In September 2012, an Israeli soldier was killed when three militants infiltrated Israel from Sinai, and in July of the same year militants shot dead a worker building a section of an Israeli barrier along the border.
Egypt signed a peace treaty with Israel in 1979 under which portions of Sinai must remain demilitarised.