BAGHDAD — U.S.-backed Iraqi government troops announced today they were in “full control” of eastern Mosul, after routing Islamic State militants from that part of the northern city almost exactly three months since the major operation started.

The achievement was a “big victory,” said Iraqi Army Lt. Gen. Talib Shaghati, who commands the counter-terrorism forces, describing the success of the Iraqi forces as “unprecedented.”

Shaghati, who spoke to reporters in the town of Bartella, just east of Mosul, said plans were now being drawn up to retake the western part of the city. He did not elaborate on when that part of the operation would begin.

Today’s advance came after Iraqi troops over the past days intensified their push into the last IS-held neighborhoods in Mosul’s eastern sector, closing in on the Tigris River, which roughly divides the city. Stiff resistance by the militants, thousands of civilians being trapped in their houses by the fighting and bad weather had in the past slowed the advances of the troops.

However, skirmishes and clashes continued in some pockets along the Tigris in eastern Mosul, according to Iraqi special forces Maj. Ali Hussein who said his unit was still pushing into the Ghabat area along the river bank. Small arms fire could be heard and at least one civilian was wounded by mortar fire.

Also, some commanders on the ground disputed Shaghati’s claim of “full control” of eastern Mosul, with Lt. Gen. Abdul-Amir Raheed Yar Allah saying the eastern side “has not been fully liberated ... and the advance is still continuing.”

Yar Allah, who commands army operations in Ninevah, where Mosul is the provincial capital, said the special forces “have done their duty” in eastern Mosul.

Mosul — the Islamic State group’s last urban stronghold in the country — fell to IS in the summer of 2014.