Nairobi, Kenya (CNN) -- Sounds of heavy gunfire erupted from Nairobi's Westgate mall Tuesday, even as authorities said for the second day they had the building under their control.
The mall "is under the full control of govt forces and we are carrying out a sweep to ensure (it's) safe for everyone," Kenyan police tweeted Tuesday.
Kenya's Interior Ministry also gave reason for hope: "We're very near the end."
But four days after Al-Shabaab terrorists stormed the swanky mall, several gunmen -- including snipers -- were still inside, two senior officials said.
And it's uncertain how many hostages might still be trapped, although Kenyan officials tweeted early Tuesday that they believed all of them had been freed.
Hours later, the sound of an explosion was heard coming from the mall.
"We are doing cleanup of explosives that had been set up by the terrorists," police said.
At least 62 people were dead, the Kenya Red Cross said in its last accounting Monday. However, the death toll would not appear to include three Kenyan soldiers reported dead by the military Tuesday, and more bodies of civilians could remain inside the besieged mall.
And while the deadly siege drags on, the families of 65 people still unaccounted for don't know whether their loved ones escaped safely, are hiding somewhere in the vast mall or might be among the dozens killed by the terrorists.
Arrests at airport
Even as soldiers continued to sweep the mall, authorities also zeroed in on an airports and border crossings. More than 10 suspects were arrested Monday for questioning in relation to the attacks, the Interior Ministry tweeted Tuesday.
Authorities also increased security at all entries and exits across the country, the nation's Immigration Department said Monday.
Kenyan forces said they have killed at least three terrorists since the siege began Saturday. Three Kenyan soldiers are dead and eight others are being treated for injuries from the mall siege, the Interior Ministry tweeted Tuesday. Roughly 175 people have been wounded, officials said.
More than 200 civilians have been rescued, the military said.