Republican presidential candidate Jeb Bush and Sen. John McCain have both called for sending additional ground troops into Syria to fight the Islamic State, with the latter proposing a force of 10,000 Americans.

"This is the war of our time," Bush said Wednesday in a speech at The Citadel, a military collage in South Carolina, just five days after Islamic State terrorists conducted attacks in Paris that killed 129 people and wounded more than 350.

"Militarily, we need to intensify our efforts in the air - and on the ground. While air power is essential, it alone cannot bring the results we seek," said Bush, a former Florida governor, reported The Huffington Post. "The United States - in conjunction with our NATO allies and more Arab partners - will need to increase our presence on the ground."

He told Bloomberg the day before that the ground force doesn't "necessarily" need to be substantial, but he did not specify a strategy at The Citadel, only saying that the number of Americans sent to the region should be "in line with what our military generals recommend, not politicians."

Should Bush win the presidency, he would be the third Bush to commit ground troops in the Middle East, according to NBC News. His father, George H.W. Bush, sent troops to Iraq in the Desert Storm war, while his brother George W. Bush engaged in Afghanistan and launched another war in Iraq that eventually led to the ousting of Saddam Hussein.

On Thursday, McCain, a former Republican presidential candidate and chairman of the Senate Armed Services Committee, also proposed sending ground troops into Syria, saying that the Islamic State group posed "a direct threat" to the U.S. and could be defeated with a significant ground deployment.

"Ground troops [means] about 10,000 Americans with a coalition of Arab countries, hopefully NATO countries, maybe even France, where we could go in on the ground with sufficient air support to take out ISIS," McCain said in an interview with France 24. "They are not invincible, there are not unbeatable."

Only 44 percent of Americans support sending ground troops into Syria, according to a poll released by Bloomberg Wednesday.