Visiting U.S. President Barack Obama on Tuesday told his troops in Iraq to be critical in next 18-month period of their mission in the war-torn country.

U.S. President Barack Obama visits Camp Victory in Baghdad, April 7, 2009. [Xinhua/AFP Photo]

Obama, who arrived in the Iraqi capital earlier in the day, made the remarks in a speech to the troops while he inspected the sprawling U.S. military base, Camp Victory, on the outskirts of Baghdad, according to media reports.

The next 18 months "is going to be a critical period," Obama said, referring to the deadline for the withdrawal of all U.S. combat troops from Iraq by August 2010.

He urged the U.S. troops to bear responsibilities to make sure Iraq is stable before the withdrawal, saying Iraq "is not a safe haven for terrorists, and we can start bringing our folks home."

Meanwhile, he also called on Iraqis to take responsibility for the country of their own.

Earlier, Obama said U.S. have made significant progress but there is still a lot of work to do in Iraq after he arrived in Baghdad.

Obama flew Baghdad in the afternoon from Istanbul at the end of his week-long international tour, making his first visit to Iraq since he took office three months ago.

He was received at the Baghdad airport by top U.S. troops commander in Iraq Gen. Ray Odierno and immediately left to a nearby U.S. military camp.

Obama is also expected to meet with Iraqi Prime Minister Nuri al-Maliki at the base just outside the capital after Obama cancelled his plan to fly with a helicopter to the heavily fortified Green Zone in central Baghdad.

His visit comes amid a new wave of car bombings in the war-torn country as the U.S. military is starting to draw down troops.

(CCTV, Xinhua News Agency April 8, 2009)