President Joe Biden released a statement Sunday calling on Congress to enact "common sense" gun control legislation in response to shootings over the weekend in Alabama and Kentucky that left a total of six people dead.

"This morning, our nation is once again grieving for at least four Americans tragically killed at a teen’s birthday party in Dadeville, Alabama as well as two others killed last night in a crowded public park in Louisville," Biden said. "Jill and I are praying for their families, and for the many others injured and fighting for their lives in the wake of this weekend’s gun violence."

As he has done in previous mass shootings, Biden urged Congress to enact gun reform legislation.

"What has our nation come to when children cannot attend a birthday party without fear? When parents have to worry every time their kids walk out the door to school, to the movie theater, or to the park?" Biden said. "Guns are the leading killer of children in America, and the numbers are rising -- not declining."

Biden said the level of gun violence in America is "outrageous and unacceptable," and noted that Americans "agree and want lawmakers to act on common sense gun safety reforms."

"Instead, this past week Americans saw national Republican elected leaders stand alongside the NRA in a race to the bottom on dangerous laws that further erode gun safety. Our communities need and deserve better," said Biden.

At least 15 people were treated for gunshot wounds at hospitals following a shooting that killed four others at a "sweet 16" birthday party in Dadeville, Alabama, officials said.

Five of the victims were in critical condition Sunday afternoon, Heidi Smith, a spokesperson for Lake Community Hospital told ABC News. Authorities later said at least 28 people were injured.

Smith said at least 15 people were initially treated at Lake Community Hospital, all suffering from gunshot wounds.

Smith said nine of the patients were in higher need of care and some were transferred to other medical facilities. Five of the patients were in critical condition, while four were in stable condition.

The ages of those hospitalized were not immediately released.

Three of the injured victims were transferred to Baptist Medical Center in Montgomery, one was transferred to Children's Hospital in Birmingham and another was moved to the University of Alabama Hospital in Birmingham, Smith said. One patient was transferred to Piedmont Hospital in Piedmont, Alabama, Smith said.

-ABC News' Elwyn Lopez

President Joe Biden has been briefed on the deadly shooting at a birthday party in Dadeville, Alabama, according to the White House.

Biden and his staff are closely monitoring the investigation and has been in touch with local officials and law enforcement to offer support, according to the White House.

An emotional Dadeville police chief pleaded for prayer for his city on Sunday and law enforcement investigators pleaded for tips from the public in finding those responsible for a shooting at a birthday party that left four dead and multiple people injured.

"The city of Dadeville is a tight-knit community, full of wonderful people. I ask you to please keep our community in your prayers. I ask you to please keep my police department in your prayers," Police Chief Jonathan Floyd said at a news conference.

Sgt. Jeremy Burkett of the Alabama Law Enforcement Agency confirmed the shooting broke out at a birthday party and asked for any witnesses to call the state police tip line.

Burkett also confirmed that four people were killed and "a multitude" of people were injured, but did not disclose the conditions of those wounded.

Burkett did not take questions during the news conference. He released no information on whether any arrests have been made in the incident.

Tallapoosa County Schools Superintendent Raymond Porter said grief counselors will be at Dadeville schools on Monday, but did not say whether any students were among the dead or injured.

The district will make "every effort to comfort" children impacted, said Porter.

"Don't lose sight of the fact that those are the ones most impacted by this situation," said Porter, who also called on local clergy to reach out to families of those killed or injured to offer assistance.

"I'm also asking that you please do not let this moment define what you think of the city of Dadeville," Floyd said. "What we're dealing with is something no community should have to endure."