By Bernie Woodall and Roselle Chen

ORLANDO, Fla. (Reuters) - Funerals for two of the 49 victims killed in the shooting at a nightclub in Florida were marked by tense scenes on Saturday, as an impatient driver was accused of injuring two law enforcement officers and another took place under the watch of anti-gay protesters.

Two Osceola County Sheriff's deputies on motorcycles were injured at the funeral procession for Jean Carlos Mendez in Kissimmee, Florida, some 20 miles (32 km) south of Orlando, when a driver cut through the cortege and struck them with her car, according to a statement on the sheriff's Facebook page.

The deputies were taken to the hospital, where both were in stable condition, said the sheriff's spokeswoman Twis Lizasuain.

At the funeral of another victim, Christopher Leinonen, at a church close to the center of Orlando, a handful of protesters from the Kansas-based anti-gay Westboro Baptist Church stood silently for about 45 minutes. They were blocked from view of those attending the funeral by about 200 counter-protesters, some holding rainbow screens, who cheered when the Westboro members left.

Authorities are still investigating what motivated Omar Mateen to kill 49 people at the popular gay nightclub Pulse in the early hours of last Sunday, perpetrating the deadliest mass shooting in modern U.S. history. Mateen was later killed in a shoot-out with police.

The shooting has sparked a new push for gun control legislation and Congress is expected to vote on proposals starting next week, including one on stopping people on terrorism watch lists from buying guns.

Democrats, including President Barack Obama, are framing gun restrictions as a national security issue after Mateen professed loyalty to Islamist militants. But authorities believe he was "self-radicalized" and acted without any direction from outside networks.

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U.S. Federal Bureau of Investigation agents on Friday questioned a member of the Florida mosque attended by Mateen, as new information surfaced revealing the killer had exhibited chronic behavioral problems during his youth.

Academic records obtained by Reuters showing Mateen was frequently suspended as a student added to a disturbing portrait of the long-troubled gunman.

Mateen, a 29-year-old private security guard, has been described by his first wife as an abusive, mentally disturbed man with a violent temper.

Others who knew him recalled Mateen, a U.S. citizen and Florida resident born in New York to Afghan immigrants, as a quiet, socially awkward individual who kept largely to himself.

The FBI has acknowledged interviewing Mateen in 2013 and 2014 for suspected ties to Islamist militant groups but concluded he posed no threat. Still, evidence in the Orlando case points to a crime at least inspired by extremist ideology.

Authorities have said Mateen paused a number of times during his three-hour siege at the Pulse nightclub to place cell phone calls to emergency 911 dispatchers and to post internet messages professing support for various Islamist militant groups.

U.S. officials have said his second wife, Noor Salman, had known of his plans to carry out the attack and a federal grand jury was convened earlier in the week to decide whether to charge Salman.

Obama, who met with survivors of the shooting and families of the dead in Orlando on Thursday, urged Congress to make it more difficult to legally acquire high-powered weapons like the semi-automatic rifle used in the attack.

The Senate is expected to vote on Monday on four proposals for limited gun restrictions, although all four are expected to fail. A group of Republican senators attempted on Friday to craft compromise legislation that might stand a better chance of passing.

(Additional reporting by Barbara Goldberg in New York and Jim Young in Orlando; Writing by Bill Rigby; Editing by Mary Milliken)