Local ceasefires in Syria went into effect on Saturday in a bid "to strengthen the currently active truce," the Syrian army said in a statement.

"All military operations will be stopped for 24 hours in Eastern Ghouta near Damascus and for 72 hours in the northern suburbs of Latakia," the statement said, according to Russia's state-owned TASS news agency.

The so-called "regime of silence" comes at a moment when the US-Russia brokered ceasefire of February 27 has all but fallen apart amid deadly fighting between rebels and Syrian government forces in and around Aleppo.

'Complex'

The US State Department said it did not push for a halt to violence in Aleppo due to the "complex" situation posed by fighting among regime forces and rebels in the northern city.

"This is a recognition that in some parts of the country, including the two parts that we've identified - North Latakia as well as Eastern Ghouta - that there has been, however you want to put it, a weakening of the cessation of hostilities," said State Department spokesman Mark Toner during a Friday press briefing.

"We want to focus on strengthening the cessation of hostilities, renewing it, reaffirming it, so that we can quell the fighting or the violations, the ongoing violations in these areas," Toner added.

Since mid-April, when the Saudi-backed mainstream opposition alliance High Negotiations Committee suspended its participation in peace talks, deadly violence has rocked the northern city of Aleppo.

Over 200 civilians have been killed since the latest wave of violence erupted on April 22, according to the UK-based Syrian Observatory for Human Rights (SOHR).

'Ensure the protection of civilians'

UN human rights chief Zeid Raad al-Hussein on Friday slammed warring parties for not doing more to safeguard civilian lives.

"Urgent action is needed by all relevant actors to ensure the protection of civilians and their right to life," al-Hussein said.

He also called on the international community "to fight the impunity that has done so much to encourage the multitude of horrendous breaches of international humanitarian law and international human rights law that have taken place in Syria over the past five years."

More than 270,000 people have been killed and roughly half the population displaced since the conflict erupted in 2011, when government forces quashed pro-democracy protests calling for President Bashar al-Assad to step down.