WASHINGTON (Reuters) – Attorney General Eric Holder said on Tuesday he had ordered the FBI to open a criminal probe in a growing scandal over the Internal Revenue Service’s targeting of conservative political groups for extra tax scrutiny.

Holder announced the Justice Department investigation as the tax agency’s embattled acting commissioner, Steven Miller, traveled to Capitol Hill for meetings on the scandal amid Republican lawmakers’ calls for his resignation.

WASHINGTON (Reuters) – President Barack Obama vowed on Monday to work to bring the Syrian government and rebels to the negotiating table in coming weeks but warned that a “combustible mix” of regional meddling and Islamist militancy would make it hard to halt the country’s civil war.

Even as Obama backed a new joint U.S.-Russian effort to seek a diplomatic solution in Syria, he cited an array of obstacles to a credible peace process, including the involvement of Iran, the Lebanese militant group Hezbollah and the al Qaeda-linked Nusra Front in the two-year-old conflict.

WASHINGTON (Reuters) – Saying it was damaging to U.S. interests to keep holding prisoners in legal limbo at Guantanamo, President Barack Obama renewed an old vow on Tuesday to close the camp, where about 100 inmates are on hunger strike to protest against their years in detention without trial.

Human rights groups welcomed Obama’s recommitment to shutting the prison, but some activists called for action, not just words.

WASHINGTON (Reuters) – President Barack Obama vowed on Tuesday to make a new push to close the Guantanamo detention center, where about 100 inmates are on hunger strike, saying it was damaging to U.S. interests to keep holding prisoners there in legal limbo.

Human rights groups have long been critical of the 12-year-old camp for foreign terrorism suspects, and their concern has intensified in recent weeks. Some of those on hunger strike are being force-fed at the camp at the U.S. Naval Base in Cuba.

WASHINGTON (Reuters) – President Barack Obama warned Syria on Friday that its use of chemical weapons would be a “game changer” for the United States but made clear he was in no rush to intervene in the civil war there on the basis of evidence he said was still preliminary.

Speaking a day after the disclosure of U.S. intelligence that Syria had likely used chemical weapons against its own people, Obama talked tough while calling for patience as he sought to fend off pressure for a swift response against Syrian President Bashar al-Assad.

WASHINGTON (Reuters) – U.S. President Barack Obama warned President Bashar al-Assad on Friday that any use of chemical weapons in Syria’s civil war would be a “game changer” but cautioned that intelligence assessments that such weapons had been deployed were still preliminary.

Speaking a day after the White House said for the first time that Assad’s government had likely used chemical weapons on a small scale, Obama talked tough while appealing for patience as he sought to fend off pressure at home and abroad for a swift U.S. response.

WASHINGTON (Reuters) – U.S. authorities have long cast a wary eye on counterterrorism intelligence from Russia, Obama administration officials say, raising questions about whether a “trust deficit” clouded efforts to determine if Boston Marathon bombing suspect Tamerlan Tsarnaev posed a danger.

Any intelligence disconnect between the United States and Russia could have broader repercussions, complicating plans to cooperate on security for the 2014 Winter Olympics in the Black Sea resort of Sochi, not far from Russia’s restive north Caucasus region.

WASHINGTON/RIYADH (Reuters) – While President Barack Obama has declared a “red line” over Syrian use of chemical weapons, U.S. officials suggested on Tuesday that Washington was unlikely to respond without clear-cut evidence of such use – evidence that may be very hard to come by.

Israel’s top military intelligence analyst said in Tel Aviv on Tuesday that Syrian government forces had used chemical weapons – probably the nerve gas sarin – in their fight against rebels trying to force out President Bashar al-Assad.

WASHINGTON/RIYADH (Reuters) – While President Barack Obama has declared a “red line” over Syrian use of chemical weapons, U.S. officials suggested on Tuesday that Washington was unlikely to respond without clear-cut evidence of such use – evidence that may be very hard to come by.

Israel’s top military intelligence analyst said in Tel Aviv on Tuesday that Syrian government forces had used chemical weapons – probably the nerve gas sarin – in their fight against rebels trying to force out President Bashar al-Assad.

WASHINGTON (Reuters) – The United States plans to provide about $100 million in new non-lethal aid to the Syrian opposition that could include for the first time battlefield support equipment such as body armor and night-vision goggles, a U.S. official said.

Secretary of State John Kerry is expected to announce the new aid package, which would mark a recalibration of U.S. policy toward rebel groups in the Syrian civil war, at an international conference on Syria that he will attend in Turkey this weekend.