Iraqi forces are battling Islamic State fighters on the eastern edge of Mosul as the two-week campaign to recapture the jihadists' last main bastion in Iraq enters a new phase of urban warfare.
Artillery and air strikes pounded the city, still home to 1.5 million people, and residents of the eastern neighbourhood of al-Quds said the ultra-hardline Sunni militants had resorted to street fighting to try to hold the army back.
Soldiers of the elite Counter Terrorism Service (CST) also entered the state television station in Mosul on Tuesday, the first capture of an important building in the Islamic State-held city since the start of the offensive about two weeks ago, the force commander, Lieutenant-General Talib Shaghati, said.
"This is a good sign for the people of Mosul because the battle to liberate Mosul has effectively begun," Shaghati said.
Iraqi troops, security forces, Shi'ite militias and Kurdish peshmerga have been advancing on several fronts towards Mosul, backed by US-led troops and air forces. Special forces units sweeping in from the east have made fastest progress.
"We are currently fighting battles on the eastern outskirts of Mosul," CTS Lieutenant-General Abdul Wahab al-Saidi said. "The pressure is on all sides of the city to facilitate entry to the city centre."
He said CTS forces had cleared Islamic State fighters from most of the eastern district of Kokjali, close to al-Quds, on Tuesday, "so now we are inside the district of Mosul".
Blackish grey smoke hung in the air east of the Islamists' stronghold and the regular sound of outgoing artillery fire could be heard, said a Reuters reporter near Bazwaia, about 5km east of Mosul.
Inside the city, residents speaking to Reuters said they heard the sounds of heavy clashes since dawn.
One inhabitant of al-Quds district at the city's eastern entrance said bullets were fizzing past and hitting the walls of houses, describing the explosions as "deafening and frightening". Many people in the area have stayed indoors for the last two days.
"We can see Daesh (Islamic State) fighters firing towards the Iraqi forces and moving in cars between the alleys of the neighbourhood. It's street fighting."
One witness said he saw nine cars, laden with families and furniture, heading from the eastern half of the to the west bank of the Tigris River to escape the encroaching frontline.
Away from the eastern fringe of the city, however, traffic was relatively normal, markets were open, and Islamic State fighters were patrolling as usual.
Mosul is many times bigger than any other city held by Islamic State in Iraq or Syria. Its recapture would mark the collapse of the Iraqi wing of the caliphate which it declared in parts of both countries two years ago, although the hardline Sunni militants have recovered from other setbacks in Iraq.
Prime Minister Haider al-Abadi said on Monday that Iraqi forces were trying to close off all escape routes for the several thousand Islamic State fighters inside Mosul.
"God willing, we will chop off the snake's head," Abadi, wearing military fatigues, told state television. "They have no escape, they either die or surrender."
Commanders have warned that the fight for Mosul, which could be the toughest of the decade-long turmoil since the US invasion which overthrew Saddam Hussein in 2003, is likely to last for months.
The United Nations has said the Mosul offensive could also trigger a humanitarian crisis and a possible refugee exodus if the civilians inside in Mosul seek to escape, with up to one million people fleeing in a worst-case scenario.