The deaths come a week after Israeli forces shot dead four Palestinians near the Gaza security fence for allegedly attempting to sneak into Israel.
Three Palestinians were killed by Israeli army fire near the Gaza security fence, the Palestinian Health Ministry said on Sunday.
A ministry statement, however, did not give further details about the deaths, which came hours after the Israeli army said its forces had fired toward armed suspects near the fence.
Last week, Israeli forces shot dead four Palestinians near the security fence for allegedly attempting to sneak into Israel.
Tension has risen along the Gaza-Israel buffer zone in recent days, with Israel accusing Gaza-based resistance factions of firing rockets from the Palestinian territory into Israel.
On Saturday, the Israeli army said three rockets had been fired from Gaza, two of them were intercepted by the Iron Dome air defence system.
Israel and Palestinian group Hamas, which rules Gaza, reached an informal ceasefire in May after the worst bout of violence since 2014.
Palestinians have been staging weekly protests near the Gaza fence to demand an end to a 12-year Israeli blockade on the coastal enclave, which has shattered its economy and deprived its two million inhabitants of many basic amenities.
Since the Gaza rallies began last year, nearly 270 protesters have been killed and thousands more wounded by Israeli troops deployed near the buffer zone.