An air raid has killed 23 civilians in a Syrian town on the border with Iraq held by the Islamic State of Iraq and the Levant (ISIL), according to a monitoring network.

The Syrian Observatory for Human Right (SOHR) said Monday's deaths in Abu Kamal were caused by an earlier morning air strikes by jets belonging to the US-led coalition fighting ISIL in Iraq and Syria.

"They hit a residential area at 3am while people were sleeping, causing the high toll," he said.

ISIL, also known as ISIS, was using apartments in the targeted area as local headquarters, he said.

The coalition, in an emailed response to the Associated Press news agency, said it did not conduct air strikes on Abu Kamal on Monday.

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In February the Iraqi air force, which is battling ISIL across the border in Mosul, carried out air raids in Abu Kamal and another nearby border town.

Monday's deaths in Abu Kamal followed those of 12 women the previous day in a raid on Akayrshi, a village in the east of Syria's Raqqa province.

Referring to the Akayrsh incident, SOHR said the women died when the US-led coalition struck vehicles carrying farm workers home from fields in the afternoon.

The attack wounded 12 other women, local sources inside Raqqa province told German news agency DPA.

They said the raid targeted a car in which the workers were returning from cotton fields.

#YPG controlled AlAtahana - Tal Maz - AlMalali villages in the northern countryside of #Raqqa yesterday. — الرقة تذبح بصمت (@Raqqa_SL) May 14, 2017

Raqqa is Being Slaughtered Silently, an activist group opposed to both ISIL and the Syrian government of President Bashar al-Assad, confirmed the news of the women's deaths in a Facebook post.

It said at least three coalition air strikes hit civilian cars over the weekend.

Raqqa is Being Slaughtered Silently also said via Twitter that the Syrian Democratic Forces (SDF) had taken control of several villages as part of an ongoing, multi-pronged offensive on Raqqa.

The coalition said that it did conduct strikes near the western edge of Akayrshi on Sunday and that it would assess the reports.

Heavy bombardment

Fighters of the SDF, an alliance of Syrian Kurds and Arabs, were about 4km from the northeastern edge of Raqqa city and 16km from its northwestern edge, the SOHR said on Sunday.

It said US-led coalition fighter jets were heavily bombarding ISIL positions in Raqqa's rural outskirts.

In November, the SDF started a major offensive aimed at capturing Raqqa, which has been occupied by ISIL since 2014.

On Friday, the SDF announced it would soon begin a final attack to capture the province.

The announcement followed US President Donald Trump's decision on Monday to approve direct arms shipments to the SDF's main fighting elements - the Kurdish People's Protection Units (YPG) - to "ensure a clear victory" over ISIL.

The war on Raqqa has already seen the YPG capture large expanses of the surrounding province with help from the US-led coalition bombing ISIL in Iraq and Syria.

This week, following months of fighting, the SDF seized the strategic town of Tabqa, to the west of Raqqa, and a major hydroelectric dam nearby.

Tabqa lies on the banks of the Euphrates River, about 55km west of Raqqa, the province's main city which has at least 300,000 residents.

Tabqa was taken by ISIL in August 2014, following its capture of Raqqa in early 2014.

The battle for Tabqa was marked by fears that the dam would be severely damaged and collapse, leading to massive flooding downstream.

The SDF said in a statement that Tabqa would be turned over to a civilian council once fully secured.

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It also said the authority that oversees the Tabqa dam would remain "a national Syrian institution that will serve all the regions of Syria without exception".

Trump's decision to arm the YPG revived a dispute with Turkey, with President Recep Tayyip Erdogan calling for an "immediate" reversal.

Turkey views the YPG as the Syrian extension of the outlawed Kurdistan Workers' Party (PKK), which has fought the state in the southeast of Turkey since 1984 and is considered a "terrorist group" by the US and the EU.