President Bush signed legislation Monday to allow states and local governments to cut investment ties with Sudan because of the violence in Darfur.

The bill permits state, county and municipal officials to adopt measures to divest their government investments from companies involved in the four sectors that provide vital revenue for Sudan's government -- oil, power production, mining and military equipment.

"I share the deep concern of the Congress over the continued violence in Darfur perpetrated by the government of Sudan and rebel groups," Bush said in a statement.

Bush's administration has raised objections to letting state and local governments adopt divestment policies that delve into foreign policy, a traditional federal role.

The president noted those concerns again Monday. Nevertheless, he agreed to signed the bill, which was approved with strong support in Congress.

Bush said the bill "risks being interpreted as insulating from federal oversight state and local divestment actions that could interfere with implementation of national foreign policy."

He emphasized that the Constitution gives the federal government the authority handle foreign relations, and that the "executive branch shall construe and enforce this legislation in a manner that does not conflict with that authority."

The aim is to pressure Sudan to ease suffering in its Darfur region.

Hundreds of thousands of people have been killed and millions driven from their homes in four years of violence in the Darfur region since ethnic African rebels took up arms against militia supported by the Arab-dominated central government.

The new law allows mutual fund and private pension fund managers to cut ties with companies involved in the major economic sectors, and provides investment managers a safe harbor from lawsuits.

The new economic pressures come on top of existing sanctions against the Khartoum government.

Bush said his administration will keep pushing for major improvements for the people of Sudan through "sanctions against the government of Sudan and high-level diplomatic engagement, and by supporting the deployment of peacekeepers in Darfur."

Bush signed the bill at his ranch in central Texas, where he was capping a few days of quiet time before returning to Washington on New Year's Day.