U.S. President Barack Obama has marked the 10th anniversary of the September 11 attacks with tributes to the first responders, the military and the thousands of people who lost their lives.

During his weekly address Saturday, Mr. Obama spoke of the acts of heroism a decade ago in New York at the World Trade Center, the Pentagon outside Washington and on United Flight 93 over Shanksville, Pennsylvania.

The president said in recent years the U.S. has taken the fight to al-Qaida, eliminating top leaders, including the mastermind of the attacks, Osama bin Laden who was killed by Navy Seals earlier this year.

Also Saturday, former U.S. President George W. Bush, who was president at the time of the attacks, attended a private wreath-laying ceremony at the Pentagon to commemorate Sunday's anniversary. Also present at the outdoor ceremony was his former defense secretary, Donald Rumsfeld.

Mr. Bush is expected to attend several other commemoration ceremonies Saturday and Sunday.

Former New York Mayor Rudy Giuliani delivered the Republican Party address Saturday, saying America is safer than it was before September 11, but not as safe as it should be. He said the country has not significantly improved port security, and that state and local governments range from very well prepared to not prepared at all.

Giuliani said U.S. security at home requires a long-term military presence in places such as Iraq and Afghanistan, where he says extremists want to kill Americans. Giuliani said politics should not influence how long troops are deployed overseas to eliminate the threat of domestic terror attacks.