Mexico says Zetas drug lord Heriberto Lazcano may be dead
Top Los Zetas drug cartel leader Heriberto Lazcano has apparently been killed in a shootout in northern Mexico, the navy says.
Officials said they were still awaiting final forensic results, but that the body appeared to be "El Lazca".
However, Mexican media later reported that the authorities may no longer be in possession of the corpse.
Lazcano is a founder of Los Zetas which has been implicated in a string of mass killings and kidnappings.
His death would be a victory in the fight against cartels, say analysts.
The state prosecutor of Coahuila state, where the shooting happened, is due to give a news conference at 15:00 GMT.
As the wait continued for confirmation of Lazcano's demise, Mexican media said that his body was reportedly missing.
The Milenio newspaper said that it seemed alleged family members had reclaimed his corpse, although it said other accounts suggested attackers had broken into the funeral home to steal the body.
Mexican police believe a recent surge in mass killings is due to a split within the Zetas cartel.
Lazcano is thought to be the leader of one faction, while the other is led by Miguel Angel Trevino Morales.
In the nearly six years of Felipe Calderon's presidency, more than 50,000 people are believed to have died in violence blamed on organised crime.
Two alleged gang members were killed in a gun battle with the navy on Sunday in the region of Progreso, some 125km (80 miles) west of the Texan border in Coahuila state.
The navy said there was "strong evidence" one of the bodies was Lazcano.
"Information was obtained after the first forensics tests were carried out that yielded indications that suggest that one of the bodies is Heriberto Lazcano," the Associated Press quoted the navy's statement as saying.
"The Navy Department is co-ordinating efforts with Coahuila state, and will be awaiting the conclusions of the forensics examination in the case," the statement said.
The navy has been at the forefront of operations against drug cartels.
Lazcano is suspected of involvement in hundreds of killings, including that of crusading newspaper editor Francisco Ortiz Franco in 2004.
The US had put up a $5m (£3.1m) reward and Mexico another $2.3m for information leading to Lazcano's capture.
On Monday the navy said it had arrested suspected regional Zetas leader, Salvador Alfonso Martinez Escobedo, who the navy says was behind the 2010 murder of 72 migrants in northern Tamaulipas state.
Officials say Escobedo works for Trevino Morales.
Trevino Morales, known as Z40, has a reputation for equal if not greater brutality than Lazcano and remains at large.
Police also recently arrested Ivan Velazquez Caballero, known as El Taliban or Z50.
He had reportedly been at war with Trevino Morales and was believed to have joined the rival Gulf Cartel.
Gulf Cartel head Jorge Costilla, alias "El Coss", was also captured last month.
Infamous for mass killings and use of extreme violence, the Zetas control key drug-trafficking routes in north-eastern Mexico.