Rockets have reportedly been fired from the Gaza Strip towards Israel, with at least one of them intercepted by Israeli missile defence system, according to Israeli government sources.
Israel's military spokeswoman said on Monday that an Iron Dome interceptor shot down one rocket launched by Palestinian fighters above the city of Ashkelon, about 12km north of the Palestinian territory.
The other rocket fell in the sea, Israeli army said. No injuries were reported.
Within hours, Israel's air force bombed what a military spokesman described as two concealed rocket launchers in northern Gaza.
There were no reported casualties and no immediate claim of responsibility either.
The Israeli military spokeswoman said a mortar bomb was also fired across the border from Gaza on Sunday, but caused no damage or casualties.
The attacks are unusual given the relative restraint of Palestinian armed groups since last November's war between the Hamas and Israel.
However, Hamas has been challenged at times by armed fighters in Gaza.
Prisoners' release planned
The incident also came as Israel released the names of 26 Palestinian prisoners to be freed as part of a US-brokered deal that led to the resumption of Middle East peace talks.
The prisoners to be released were jailed for the killings of Israelis before the beginning of Israeli-Palestinian peace talks in 1993.
Hamas, which governs Gaza, plunges into financial and political crisis after being cut off from neighbouring Egypt by the new, military-guided interim government in Cairo.
Hamas has tried to mend ties with Egypt while appealing to Palestinian President Mahmoud Abbas, whose administration holds sway in the occupied West Bank, to abandon US-sponsored peace talks with Israel.
It has also signalled readiness to fight again, taking responsibility last week for a tunnel which the Israelis discovered running into their territory from Gaza and said was probably intended for kidnapping soldiers or setting off underground explosives.
For its hard, Israeli troops seized two Hamas legislators and 23 other Palestinians in the West Bank on Monday, according to the Ramallah-based Palestinian Authority.
Israeli authorities did not immediately comment on the arrests.