AKIPRESS.COM - A joint command center made up of the forces of Russia, Iran and militias supporting Syrian President Bashar al-Assad on Sunday said the U.S. strike on a Syrian air base on Friday crossed "red lines" and it would respond to any new aggression and increase its support for its ally, Reutersreported.

The United States fired dozens of cruise missiles at a Syrian air base on Friday from which it said a deadly chemical weapons attack had been launched earlier in the week, escalating the U.S. role in Syria and drawing criticism from Assad's allies including Russia and Iran.

"What America waged in an aggression on Syria is a crossing of red lines. From now on we will respond with force to any aggressor or any breach of red lines from whoever it is and America knows our ability to respond well," said the statement published by the group on media outlet Ilam al Harbi (War Media).

U.S. Secretary of State Rex Tillerson, meanwhile, blamed Russian inaction for helping fuel the chemical weapons attack it had reacted to, saying Moscow had failed to carry out a 2013 agreement to secure and destroy chemical weapons in Syria.

He said the United States expected Russia to take a tougher stance against Syria by rethinking its alliance with Assad because "every time one of these horrific attacks occurs, it draws Russia closer into some level of responsibility."

Rebels and residents in northwestern Idlib province said jets believed to be Russian conducted eight raids on Sunday on the town of Khan Sheikhoun where the chemical attack took place but no casualties were reported.

Raids hit several other rebel-held towns including Saraqeb and Sarmin in the province, where the rebels and activists said incendiary bombs were dropped.

The death toll from an air strike on Saturday on the rebel-held town of Urum al-Joz in Idlib province rose to 19 people, including six children, activists and residents said.

In the southern city of Daraa, jets believed to be Russian escalated strikes on Free Syrian Army (FSA) and jihadist groups on Saturday and Sunday in an attempt to roll back their gains in the Manshiya district where battles have been raging for nearly two months.