“I welcome that the UN Security Council has now demanded an immediate halt to all military activities to and from Gaza,” Bildt said in a statement.
The comments come as Israeli air strikes in Gaza continued for a second day in response to repeated mortar attacks launched by Palestinian militants.
By Sunday, an estimated 280 Gaza residents had been killed and 600 injured by the Israeli strikes, according to the New York Times newspaper.
Bildt also noted the importance of the Security Council’s recognition of the “serious economic and humanitarian situation” facing Gaza’s population and that the body calling for measures to “ensure the people can receive food, fuel, and medical help”.
“Both Hamas and Israel ought to, against this background, declare as quickly as possible that they are willing to return to their earlier ceasefire and halt all combat operations,” said Bildt.
Bildt also called for border crossings to be opened to allow international aid and other supplies to reach “Gaza’s hard stricken people”.
The foreign minister’s comments come a day after he characterized the Israeli attacks as “a serious continuation of the heightening of tensions” which began when Hamas just before Christmas decided not to renew a six-month ceasefire.
“Even if the ceasefire didn’t live up to expectations – not least when it came to easing the Israeli blockade of Gaza – it would have been better for everyone if it had continued to be respected,” said Bildt.
“We strongly urge both parties to exercise moderation and to as soon as possible return to the ceasefire.”