BAGHDAD — Prime Minister al-Maliki of Iraq, in a visit to Iran where he met yesterday with president Ahmadinejad, pledged closer ties between the two neighbors at the same time Baghdad is negotiating a long-term security agreement with America.

The proposed pact with Washington, D.C., would establish a legal framework for the continued presence of American troops in Iraq after the United Nations mandate expires at the end of this year.

Iranian officials repeatedly have expressed concerns in recent weeks that the agreement simply will formalize the presence of dozens of American military bases.

In a roundtable public affairs program broadcast on Iranian television, one panelist compared American bases in Iraq to the installation of Russian missiles in Cuba during the Cold War between America and the Soviet Union.

But Mr. Maliki, after meeting with Mr. Ahmadinejad, said the agreement would help maintain and enhance Iraq’s still-fragile security situation.

“A stable Iraq will be a benefit to the security of the region and the world,” Mr. Maliki said, according to Mr. Ahmadinejad’s official Web site.

Mr. Ahmadinejad, for his part, indicated concerns that an agreement could lead to long-term American domination of Iraq.

“Iraq must reach a certain level of stability,” he said, according to an Associated Press report, “so that its enemies are not able to impose their influence.”

Mr. Maliki, after arriving in Tehran, the Iranian capital, Saturday, had said his government “will not allow Iraq to become a platform for harming the security of Iran,” according to the semi-official Fars News Agency.

Mr. Maliki’s three-day visit to Iran is his third since taking office in May 2006. Relations between the two former enemy nations have flourished since the American-led ousting of Saddam Hussein allowed Iraq’s long-persecuted Shiite Muslim majority to rise to political power. Like many Shiite politicians, Mr. Maliki spent part of the Saddam years in exile in Shiite-dominated Iran.

American officials have accused Iran of helping destabilize Iraq by supplying weapons to Shiite militias. But despite American reservations, ties between the two nations continue to grow, and Iran has signed an agreement to supply electricity to Iraq and build power plants in several Iraqi cities.

Saddam waged a devastating eight-year war with Iran in the 1980s, backed by America and several Arab nations, who feared the spread of Iran’s Islamic revolution. Earlier this year, Mr. Ahmadinejad visited Baghdad in the first visit by an Iranian president since 1979.

In northern Iraq yesterday, a suicide bomber in the province of Tamim killed one American soldier and wounded 18 others, the U.S. military said. A second soldier was killed Saturday in eastern Baghdad when his vehicle was struck by a roadside bomb.

Iraqi police reported that four bullet-riddled bodies were found in the capital yesterday.