The U.N. Security Council has swiftly and strongly condemned North Korea's latest ballistic missile launches and threatened to take "further significant measures" if necessary.
United Nations resolutions bar North Korea from any use of ballistic missile technology.
South Korea in July announced the deployment of the advanced anti-missile system in the southern part of the country.
Bolstering the sanctions will involve closing loopholes in existing measures, the Wall Street Journal quoted Obama as saying after a meeting with South Korean leader Park Geun-hye in Vientiane.
Asked whether China agreed more significant measures needed to be taken, permanent United Kingdom representative to the U.N., Matthew Rycroft, said: "We're talking to all of our council colleagues".
Monday's missile launches were the latest in a series by North Korea this year in violation of Security Council resolutions that were supported by China banning ballistic missile-related activities by Pyongyang.
The Council members said they further regretted that the North Korea is diverting resources to the pursuit of ballistic missiles while it citizens have great unmet needs.
Even after receiving worldwide warnings and appeals, North Korea has proceeded to engage in provocative acts such as its launch of the three mid-range Rodong ballistic missiles on Monday and a test-firing of a submarine-launched ballistic missile (SLBM) on August.
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North Korea has been hit by five sets of United Nations sanctions since it first tested a nuclear device in 2006.
North Korean officials could not be reached for comment.
North Korea has been under United Nations sanctions since 2006.
In light of the repeated missile launches, the Japanese and USA governments are seeking further measures to impose on North Korea, including additional sanctions. The missiles were launched "without giving any prior navigational warning", a statement by the South Korean military said.
Last month, it successfully tested a submarine-launched missile and development of those missiles would add a weapon that is harder to detect before launch.
Earlier Tuesday, U.S. Ambassador to the U.N. Samantha Power urged the council to act to enforce earlier resolutions that prohibit the reclusive Stalinist state from conducting ballistic missile-related activities and impose sanctions.
South Koreans watch a news program reporting about North Korea's missile launch.
"We were able to come together as a council to condemn the last launches in August and I think we have every expectation that we will do so again", Power said.
