"Once again, Israel faces a barrage of deadly rocket attacks by terrorist groups Hamas and Islamic Jihad. We support Israel 100% in its defense of its citizens…", he tweeted.
He also addressed the people in the Gaza Strip.
"To the Gazan people — these terrorist acts against Israel will bring you nothing but more misery. END the violence and work towards peace — it can happen!" the president wrote.
READ MORE: IDF Says Sirens Sound in Southern Israel for Second Day In Row
US Vice President Mike Pence also slammed the Hamas attacks and stated that Washington stood with its "great ally" Israel, according to his statement on Twitter.
"We strongly condemn the attacks in Gaza by Hamas terrorists. Israel has the absolute right to defend itself & the U.S. stands by our great ally Israel", Pence tweeted.
Earlier, the Israel Defence Forces said that air-raid sirens had sounded across southern Israel for a second straight day.
Tensions in the Gaza Strip escalated early Saturday when the Israeli military said they detected dozens of rockets fired from the area. The IDF responded by hitting Hamas and other targets. The Israeli military also attacked a building where Hamas' military intelligence and general security offices in the Gaza Strip were located.
According to media reports, at least 24 Palestinians, including a pregnant woman and her baby, as well as four Israelis were killed over the weekend.