U.S. aircraft carried out 18 strikes on Islamic State positions near the besieged Syrian border town of Kobani on Tuesday and Wednesday, the U.S. military's Central Command said.
U.S planes also conducted five strikes against Islamic State militants in Iraq, it said in a statement on Wednesday.
Meanwhile, Kurdish forces making a stand against Islamic State fighters in Kobani said they have begun coordinating with the U.S. military to provide targets for air strikes, helping to halt the advance of the fighters through the Syrian frontline town.
A four-week siege of the mainly Kurdish town on the border with Turkey has become a focus of the U.S.-led effort to halt the militants who have seized swathes of territory in Syria and Iraq.
The United Nations has warned that a massacre could take place in the town if it falls to militants, who now control nearly half of it after pushing their way inside last week.
A U.S.-led alliance has been bombing Islamic State targets in Iraq since August and extended the campaign to Syria in September. After weeks in which Kobani was rarely targeted, the town has become the main focus of strikes in recent days.
The U.S. military said it and its allies conducted 21 attacks on the militants near Kobani on Monday and Tuesday and appeared to have slowed Islamic State advances there, but cautioned that the situation was fluid.
The air strikes, visible from across the frontier in Turkey, have clearly intensified in recent days, and a monitoring group said they have become more effective, killing at least 32 Islamic State fighters in direct hits on the town this week.
Kurdish officials said the improvement in the effectiveness of air strikes in and around Kobani had come about after the main Kurdish armed group, the YPG, began giving the coordinates of Islamic State positions to the U.S.-led alliance.
The Kurdish YPG have been struggling to defend Kobani, also known as Ayn al-Arab, from better armed Islamic State fighters who have used tanks, artillery and suicide truck bombs in a month-long offensive against the town at the Turkish border.
Kobani appeared close to falling a week ago as Islamic State fighters entered its eastern and southern districts and flew their black flag. As recently as Saturday, Kurdish leaders were calling for the air strikes to be stepped up.
But in recent days, the air strikes have increased and the militants have not made much progress.
The Kurds say they have taken back areas on the west of the town.
The Syrian Observatory for Human Rights, which tracks the war using a network of sources on the ground, said one of the allied air strikes in the last day killed a group of Islamic State fighters just 50 meters (yards) from a Kurdish position.
Rami Abdulrahman, who runs the Observatory, said seven Islamic State fighters had been killed in clashes with the Kurds on Wednesday, compared to five Kurdish fighters.
"The air strikes are more serious than before because the coordination has grown in the last six days," Abdulrahman said.
On another note, SANA said gunmen opened fire on a Syrian lawmaker in his car outside Hama city in the west of the country, killing him and another civilian.
It said the attack on Waris al-Younes took place late on Tuesday and was carried out by unidentified "terrorists" - a reference to insurgents opposing government forces in Syria's more than three-year-long conflict.
Pro-government forces regularly clash with groups including al Qaeda's Nusra Front and other Islamist battalions in Hama.
The province is in a stretch of territory in Syria's west that is a priority for Damascus.
Younes, who was in his mid-40s, represented Hama province in the Syrian parliament, the report said, adding that he had died from bleeding from a gunshot wound to his chest. A civilian in another car nearby was also killed, it added.
On Wednesday Syrian warplanes carried out raids on the countryside in the east of Hama province and helicopters dropped barrel bombs in the north, according to the Britain-based Syrian Observatory for Human Rights which tracks the conflict.
On the ground, pro-government forces fought with Nusra Front and Islamist battalions in the north, the Observatory said.
There have been several attacks targeting Syrian government officials since the start of the crisis in 2011.
In 2012, a suicide bomber killed three of President Bashar al-Assad's top military officials in the capital and last April the prime minister survived a bomb attack on his convoy in Damascus, which killed six.
REUTERS