BAGHDAD — Top Sunni politicians on Wednesday accused Iraq's Shiite-dominated security forces of carrying out political arrests and warned that this could push Iraq into another round of sectarian fighting.

The outcry came in response to the high-profile arrests Tuesday of three Sunnis — the son of a senior politician, a university president and a provincial council member.

The arrests could upset the delicate political cooperation between the Shiite majority and Sunni minority in parliament.

The Sunnis' angry words — though not backed by specific threats of action — highlighted the country's stubborn religious divisions. Sectarian hatred pushed Iraq to the brink of all-out Sunni-Shiite civil war two years ago, though recent months have seen a sharp drop in violence.

Despite its domestic troubles, Iraq's Shiite-led government took another step toward wider recognition Wednesday, winning a pledge of support from visiting Lebanese Prime Minister Fuad Saniora. Since the U.S.-led 2003 invasion of Iraq, the country had been largely isolated.

Saniora, a Sunni, was only the third senior Arab politician to visit since the war. Iraqi Prime Minister Nouri al-Maliki said the two countries would sign trade deals, including on the sale of Iraqi oil to Lebanon. The Lebanese are expected to get a discount, one official said.

The latest round of arrests began early Tuesday, with raids in the town of Baqouba in the volatile Diyala province, where a university professor and provincial council member were taken.

Late Tuesday, security forces arrested the son of a senior Sunni politician, Adnan al-Dulaimi. Al-Dulaimi said troops arrested his 44-year-old son, Muthanna, at the family's home in western Baghdad. Another son was detained eight months ago. Al-Dulaimi said Muthanna is not involved in politics, and that his arrest was meant to silence his father instead.

An Iraqi military spokesman, Maj. Gen. Qassim Atta, told the state-run Iraqiyah TV that Muthanna al-Dulaimi is suspected of involvement in sectarian killings, forcing Shiites out of certain areas and banning displaced families from returning.

Security officials have also alleged that the Diyala university president and the member of the provincial council were suspected in sectarian killings, and would be brought before a judge. Sunni politicians dismissed the claims as a pretext for political arrests.

But Saleh al-Mutlaq, leader of the second largest Sunni party in parliament, said he believed Tuesday's arrests were politically motivated.

"I think what happened yesterday represents a struggle between Sunni and Shiite politicians, and some are trying to settle old scores," al-Mutlaq, one of the drafters of the Iraqi constitution, told The Associated Press.

"It seems to me that some leaders of the security forces are trying to ignite sectarian strife again," he said.

The largest Sunni bloc in parliament, the National Accordance Front, condemned the arrests as "provocative" and also warned that they are undermining attempts at reconciliation.