ANNE BARNARD

The boom of airstrikes and missile attacks echoed across Aleppo, Syria, through the night Wednesday and into Thursday, as the government and its allies continued their attacks on the rebel-controlled half of the city.

The second day of a partial truce in Syria was marred on Sunday by a number of airstrikes and artillery attacks, the warring sides reported, demonstrating the challenges of even a limited deal.

Airstrikes hit four hospitals in rebel-held northern Syria on Monday, including child and maternity facilities, international aid officials and witnesses reported. The United Nations said at least 50 people were killed, including children.

Airstrikes destroyed a hospital in northern Syria on Monday, leaving eight staff members missing, according to Doctors Without Borders.

Syrian government and allied forces pressed their most dramatic advance in months Friday, sending insurgents scrambling and tens of thousands of civilians fleeing toward the border with Turkey.

Syrian government and allied forces pressed their most dramatic advance in months Friday, sending insurgents scrambling and tens of thousands of civilians fleeing toward the border with Turkey.

After nearly five years of civil war in Syria, the United Nations estimates that 400,000 people are trapped behind battle lines by the government, the Islamic State or rival insurgents.

In the hills near the Lebanese border, an hour’s drive from downtown Damascus, much of a Syrian town is starving, according to residents and international humanitarian workers.

Once united under the Qaida brand, the groups split over differing strategies in Syria. The Islamic State has since emerged as the most dynamic, popular force among radicalized Muslims who see bloodletting as the best way to advance an Islamist agenda.

The bombings, near a Palestinian refugee camp that has absorbed many Syrians, killed at least 43 people, according to the Lebanese Health Ministry.

Russian warplanes are carrying out more airstrikes in support of Syrian government ground troops as rebels are firing more U.S. anti-tank weapons, deepening the impression that a proxy war between the United States and Russia is joining the list of interlocking conflicts in Syria.

Backed by Russian warplanes, the Syrian army began a ground offensive Wednesday against rebel forces in northern Hama province, while the Kremlin said it had fired 26 cruise missiles on Syrian targets from naval vessels in the Caspian Sea.

Ideologically unified, the Islamic State is emerging as a social and political movement in many Sunni areas, filling a void in the absence of solid national identity and security.

Militant fighters of the Islamic State launched one of their fiercest attacks in months Wednesday, setting off 21 car bombs in the city of Ramadi, even as they were losing ground to an Iraqi government offensive in Tikrit, security officials said.