WASHINGTON (CNN) -- Several 2008 presidential candidates have reacted to the Virginia Tech shootings either through issued statements or on their campaign Web sites.

Sen. Joe Biden, D-Delaware
"Today's horrific events at Virginia Tech have shocked us all. There are few comforting words in such senseless times as these. Our humble thoughts and prayers go out to the victims' families and loved ones. We will grieve as a nation together with all those affected by this terrible tragedy." (Issued statement)

Sen. Sam Brownback, R-Kansas
"This is an unbelievably tragic time for the Virginia Tech community, and our thoughts and prayers are with the victims and their families. This is a sad time for the country, and we will remember all the people who have been touched by this tragedy." (Issued statement)

Sen. Hillary Clinton, D-New York
"I am shocked and saddened by the horrific tragedy at Virginia Tech. My prayers are with the victims and their families, as well as the students, faculty, and community devastated by these gruesome killings. As a parent, I am filled with sorrow for the mothers and fathers and loved ones struggling with the sudden, unbearable news of a lost son or daughter, friend or family member. This tragedy is still unfolding and I hope as a nation we can come together and keep in our thoughts all those affected as we learn more about the events which took place this morning." (Issued statement)

Sen. Chris Dodd, D-Connecticut
"Today's events at Virginia Tech mark a very sad day in American history. My prayers are with the families who lost loved ones. My thoughts are also with the innocent victims who were injured, and I pray that they stage full and speedy recoveries. I am deeply saddened by this unnecessary loss of life, but I believe our nation will find the strength to support those touched by this tragedy." (Issued statement)

Former Sen. John Edwards, D-North Carolina
"We are simply heartbroken by the deaths and injuries suffered at Virginia Tech. We know what an unspeakable, life-changing moment this is for these families and how, in this moment, it is hard to feel anything but overwhelming grief, much less the love and support around you. But the love and support is there. We pray that these families, these students, and the entire Virginia Tech community know that they are being embraced by a nation. There is a Methodist hymn that gave us solace in such a moment as this, and we repeat its final verse here, in hopes it will help these families, as it helped us:

'In our end is our beginning; in our time, infinity;
In our doubt there is believing, in our life, eternity,
In our death, a resurrection; at the last, a victory,
Unrevealed until its season, something God alone can see.'

Our dearest wish is that this day could start again, with the promise of these young people alive. Knowing that cannot be, our prayer is for God's grace and whatever measure of peace can be reached on this terrible day." (Issued statement)

Former GOP New York City Mayor Rudy Giuliani
"On this day of national tragedy, when we lost some of our finest to a senseless act, we stand together as a country to mourn those who lost their lives. My thoughts and prayers continue to be with the survivors and the many friends, colleagues and family members of those who perished. May God bless them all."

Sen. John McCain, R-Arizona
"I am shocked and saddened to hear the news of today's events. This inconceivable tragedy was a horrific act of cruelty that took the lives of so many innocent young people, cutting their lives short and inflicting tremendous pain on all of those who loved them. Cindy and I extend our deepest sympathies and prayers to the students, faculty, friends and family of the Virginia Tech community."

Sen. Barack Obama D-Illinois
"There are going to major tragedies that we hear about as we heard about today at Virginia Tech and I can only imagine what its like for parents who still can't get in touch with their kids from all over the country. We pray for them." (During a campaign event in Chicago)

Gov. Bill Richardson, D-New Mexico
"On behalf of all New Mexicans, Barbara and I extend our condolences to the families of the victims whose lives were cut short by this horrific tragedy. This is a sad day and our hearts go out to the Virginia Tech community as it grieves this loss." (Issued statement)

Former Gov. Mitt Romney, R-Massachusetts
"The entire nation grieves for the victims of this terrible tragedy that took place today on the campus of Virginia Tech. Our thoughts and prayers are with the victims, their families and the entire Virginia Tech community. Our full support is behind the law enforcement officials who are involved with stabilizing the situation and conducting an investigation."

Rep. Tom Tancredo, R-Colorado
"I can only offer my thoughts and prayers to those kids, their family and friends at Virginia Tech today. This senseless violence cannot be justified nor the motives of the monster who committed it ever be fully understood. This is a dark day in our history as the lives of so many promising young kids have been cut short by a disturbed and evil person. From experiencing our own tragic event (Tancredo's district includes Columbine High School) whose anniversary is only a few days away, I can say with some encouragement that in time, wounds do heal." (Issued statement)