BEIRUT - Russian-backed Syrian government forces have all but encircled Islamic State militants in the eastern city of Deir el-Zour, a group that monitors the war said Wednesday.

The state-run news agency SANA said pro-government forces are battling the militants in the village of al-Husseiniyeh on the eastern bank of the Euphrates River, across from the remaining militant-held pockets in the city. The Britain-based Syrian Observatory for Human Rights said retaking al-Husseiniyeh would leave the militants fully surrounded.

Syrian forces have advanced since early September on Deir el-Zour, breaking an IS siege on government-held parts of the city. U.S.-backed Syrian forces are battling the militants on the eastern side of the river in a separate offensive.

The race for control of territory and resources in the oil-rich province that borders Iraq has caused friction between the two sides. The U.S-backed fighters say government forces and Russian warplanes have attacked them. Russia warned it would retaliate after it said Syrian government troops came under fire from the U.S-backed forces.

Russia and the United States say they are working out a mechanism to avoid friction in the common fight against Islamic State militants.

Elsewhere in Syria, a Russian airstrike killed five senior members of an al-Qaida-linked group operating in the northwest, the Russian Defence Ministry said. Maj. Gen. Igor Konashenkov, a ministry spokesman, said the five were responsible for the attack on Russian military police in Hama province last week. He did not specify when the airstrike took place.

The Russian military said the airstrike was based on intelligence about an upcoming high-level meeting of the leaders of al-Qaida-linked Levant Liberation Committee south of the city of Idlib. It said the five included the leader of the group's unit in south Idlib province, a financial chief, and an adviser to one of the group's ideologues, Saudi cleric Abdullah al-Muhaysini.

Three Russian troops were wounded after militants encircled 29 Russian military officers deployed outside Idlib for several hours during an insurgent offensive. The Russian troops repelled the attack with the help of local tribes.

Russia and the Syria have since then undertaken an intense aerial campaign in the area, striking both military and civilian targets, according to monitors.

The New York-based Physicians for Human Rights monitoring group said Wednesday it believed one of the two militaries was responsible for airstrikes that damaged three hospitals on Sept. 19. The group called it the worst attack on hospitals in Syria since April, and said two of the hospitals were later struck again.

PHR and other watchdogs say the Syrian government has intentionally targeted medical workers and hospitals throughout the six-year-old civil war. The organization has documented attacks on 323 medical facilities since the start 2011. The vast majority were committed by Russian or Syrian government forces

___

Associated Press writer Nataliya Vasilyeva in Moscow contributed to this report.

News from © The Associated Press, 2017