The first blast destroyed a motorcycle as it passed a police checkpoint with two riders aboard, witnesses said. Two policemen were killed and a third Palestinian wounded. It was not immediately clear if the riders were among the casualties.
The second explosion, less than an hour later, wounded several people at a police checkpoint elsewhere in the city, the interior ministry said. The ministry declared a state of emergency throughout Gaza, putting security forces on alert.
It wasn't immediately clear who was responsible for the attacks.
Hamas chief Ismail Haniyeh stressed that Gaza can "absorb" such incidents.
"We are certain things will be controlled and all sides involved in these bombings will be held accountable," he said in a statement.
A Hamas health ministry spokesman initially blamed Israel, but later deleted his statement on Twitter. The Israeli military said it was unaware of any action in the Gaza Strip.
The blasts came amid rising tensions between Israel and Hamas, with Israel restricting the gas supply to the Palestinian enclave on Monday after rocket fire at southern Israel.
Please click to read our informative text prepared pursuant to the Law on the Protection of Personal Data No. 6698 and to get information about the cookies used on our website in accordance with the relevant legislation.
6698 sayılı Kişisel Verilerin Korunması Kanunu uyarınca hazırlanmış aydınlatma metnimizi okumak ve sitemizde ilgili mevzuata uygun olarak kullanılan çerezlerle ilgili bilgi almak için lütfen tıklayınız.