South Korean President Park Geun-hye arrived in Seoul on Wednesday after a two-nation tour to the United States and Mexico focused on security and economic cooperation.

In Washington, Park held a series of talks with leaders of the U.S., China and Japan that resulted in them agreeing to enforce the toughest-ever sanctions resolution on North Korea.

The consensus sent a clear message to North Korea: give up its nuclear ambitions and provocations or face even tougher sanctions and isolation.

The development could boost Park's stance to pressure North Korea into abandoning its nuclear program.

The North is under U.N. sanctions for carrying out its fourth nuclear test and a long-range rocket launch earlier this year in defiance of international pressure.

Still, North Korea has shown no signs of relenting on its nuclear policy despite the mounting pressure.

North Korea views its nuclear program as a powerful deterrent that can ensure its survival against what it claims is Washington's hostile policy towards it.

Park has pledged to join international efforts to develop nuclear security regimes amid growing concerns over possible nuclear and radiological attacks by terrorist groups.

The chief executive also secured support from her Mexican counterpart, Enrique Pena Nieto, for the U.N. sanctions on North Korea.

Pena Nieto told Park in Mexico City that Mexico is handling a North Korean freighter in a manner that fully adheres to its obligation as a member of the U.N.

Mexico has vowed to continue to detain the freighter despite North Korea's protests, a South Korean official said.

The North American country detained the Mu Du Bong after identifying the ship as belonging to Ocean Maritime Management, a North Korean firm blacklisted by the U.N. for illegally shipping arms.

Park and Pena Nieto agreed to hold working-level talks later this year on a free trade deal between the two sides.

South Korea and Mexico launched free trade talks in 2007, but the negotiations have been stalled since 2008 due to strong opposition from the Mexican automobile industry.

Park and Pena Nieto observed the signing memorandums of understanding that Seoul says could help South Korean companies participate in infrastructure projects.

Mexico is pushing for projects worth US$590 billion to modernize such sectors as energy, transport and water resources management.

Separately, more than 110 South Korean companies held two separate business meetings with American and Mexican buyers in Los Angeles and Mexico City to explore new business opportunities.

Some of them signed deals worth $254 million, according to South Korean officials. (Yonhap)