In a presidential statement read by Indian Ambassador to the UN, Hardeep Singh Puri, the Council called for an immediate end to violence and asked all sides to act with "utmost restraint, and to refrain from reprisals, including attacks against state institutions."
India holds the Council's rotating presidency this month.
"The Security Council expresses its grave concern at the deteriorating situation in Syria, and expresses profound regret at the death of many hundreds of people. The Council condemns the widespread violations of human rights and the use of force against civilians by the Syrian authorities," the statement read.
At least 120 individuals have reportedly been killed in the city of Hama since Friday as security forces used tanks, mortar shells and heavy machine guns against civilian demonstrators.
The Council stated the Syrian authorities should respect human rights and comply with their obligations under applicable international law.
"Those responsible for the violence should be held accountable."
The Council also expressed regret over the lack in progress in implementing the reforms.
The statement came after days of deliberations among the 15-member body on how to react to the large scale violence, killings and arrests in the Syrian uprising.
UN Secretary General Ban Ki-moon welcomed the Security Council's statement, saying it is the "clear message of the international community."
He asked Syrian President Bashar al-Assad to immediately cease all violence against his people and to "fully respect human rights." Terming the actions in Syria "as brutally shocking", Moon said the killings should be investigated fully, independently and transparently and those responsible should be held to account.
"The legitimate aspirations of the Syrian people must be addressed through an inclusive Syrian-led political process that guarantees fundamental freedoms and rights for all."