Beirut: Syrian troops and militia fought fierce battles with Daesh terrorists in Syria’s northeast overnight, war monitors and state media said on Wednesday, as both sides vie for control of territory near the Iraqi frontier.

Some of the biggest battles took place near a prison just south of Hasakah city after Daesh set off a bomb close by, the British-based Syrian Observatory for Human Rights said.

State television also reported the clashes, saying they were fought around the prison under construction. Daesh terrorists had been trying to break into the unfinished building after setting off five car bombs, it said in a newsflash.

The surrounding Hasakah province, the country’s northeastern triangle bordering on Turkey and Iraq, is a strategic area because it links up Daesh-held land in Syria and Iraq.

Steady advances by rebels on key fronts in Syria have increased military pressure on President Bashar Al Assad, whose government increasingly sees western areas near the capital and the coast as its priority in the four-year-old conflict.

Syria’s Hasakah province is mainly populated by Syrian Kurds, whose YPG forces have pushed back the Al Qaida offshoot in other areas across Syria’s north with the help of US-led airstrikes.

Battles were also taking place between Daesh and Kurdish forces close to Ras Al Ain, a town on the border with Turkey northwest of Hasakah city, the Observatory said.

The YPG says it does not coordinate its operations with the Syrian military.

The United States and its allies have launched 10 air strikes against Daesh targets in Iraq and five in Syria since Monday morning, the US military said on Tuesday.

The five strikes in Syria were concentrated near Hasakah and Kobani further to west, and hit tactical units, fighting positions, a command and control facility and a weapons cache, it said.

The Observatory, which collects its information from a network of sources on the ground, said around 30 fighters from the Syrian military and allied militia had been killed in five days of battles with Daesh in Hasakah province.

State news agency SANA said late on Tuesday that the army had “eliminated” a large number of Daesh terrorists in the Hasakah countryside and foiled an attack on military outposts in rural areas in the east and southwest.