WASHINGTON – A federal grand jury in Miami is investigating Sen. Robert Menendez, D-N.J., examining his role in advocating for the business interests of a wealthy donor and friend, according to three people aware of the probe.

Menendez has intervened in matters affecting the financial interests of Florida ophthalmologist Salomon Melgen, seeking to apply pressure on the Dominican government to honor a contract with Melgen’s port security company, documents and interviews show.

Melgen has provided Menendez with plane flights and hospitality at his Dominican vacation home, say people acquainted with their relationship.

US, Afghanistan differ on detainees

A dispute over the fate of about three dozen militants held by U.S. forces in Afghanistan has disrupted negotiations over a long-term security agreement to leave U.S. troops in the country after 2014.

The United States has refused to turn over the prisoners – deemed especially dangerous compared with more than 3,000 already transferred to Afghan control – unless President Hamid Karzai guarantees they will not be released. He has so far declined.

The U.S. commander in Afghanistan, Gen. Joseph Dunford Jr., ordered U.S. troops to intensify security measures out of concern that Karzai’s statements are creating a greater risk of attack from rogue Afghan security forces and insurgents.

TSA affirms plan to allow small knives

The head of the Transportation Security Administration told lawmakers Thursday he stands by his plan to let passengers carry small knives onto planes despite opposition to the proposal.

It’s unlikely in these days of hardened cockpit doors and other preventive measures that the small folding knives could be used by terrorists to take over a plane, TSA Administrator John Pistole told a hearing of the House Homeland Security Committee.

On the other hand, searching for the knives on passengers or in their carry-on bags is time-consuming, Pistole said.