"Our presence in government is an affair that concerns the Lebanese people, and US intervention ... goes against democracy," Hizb Allah representative and new energy minister Muhammad Fneish said on Wednesday.
"As a politically and militarily representative force in Lebanon, what interests us is serving our people, not whether it pleases the United States or not," he said in a statement.
US State Department spokesman Adam Ereli said on Tuesday that no official decision has been made regarding Fneish's inclusion in the new cabinet, which still must be confirmed by the Lebanese parliament.
However, "to the extent that there were members of Hizb Allah, active members of a foreign terrorist organisation that are present in the government, our ability to deal with those individuals is circumscribed by law", Ereli said.
"We have a policy toward Hizb Allah. It's clear. It hasn't changed."
Fneish said: "Our problem is with US policy and that Washington does not want to forgive the resistance for having liberated our land and having hunted their allies, the Israelis in the south (of Lebanon)."
The Shia Muslim Hizb Allah spearheaded the resistance that led to Israel's withdrawal from southern Lebanon in May 2000.
"As a politically and militarily representative force in Lebanon, what interests us is serving our people, not whether it pleases the United States"
Hizb Allah minister
The group, which continues to be involved in sporadic clashes with Israel on the tense border, exclusively patrols the formerly Israeli-occupied south and has had representatives in government since 1992.
During legislative elections in May-June, Hizb Allah allied with the Shia movement Amal and other pro-Syrian factions to gain 35 of 128 seats in parliament.
Hizb Allah, which is supported by Tehran and Damascus, has 14 parliament seats.
Its participation in government is likely to pose a problem for the international community, which demands that Hizb Allah - regarded in Lebanon as a legitimate resistance to Israel - give up weapons.
Hizb Allah is against disarmament, which it calls an "internal matter" that must be resolved within Lebanon.
Syria's prime minister has said disarming Hizb Allah will turn Lebanon into a playground for Israeli intelligence and will threaten Syria's national security.
Prime Minister Muhammad Naji Otari told Kuwait's Al-Anba daily in comments published on Wednesday that "taking away the weapons of the resistance will make Lebanon open territory for the Israeli Mossad (spy agency) ... to play in as it wants".
The interview took place in the Syrian capital, Damascus.
Otari (R): Disarming Hizb Allah
threatens Syria's security
"In addition to that, it will threaten the national security of Syria, and that is the most important point for us," Otari said. He did not elaborate.
Asked if he thought Syria would be Washington's next military target, Otari said: "I don't think so, because America cannot get out of Iraq, cannot get out of the quagmire it is in. It cannot open a new front."
Washington accuses Syria of supporting "terrorist organisations" including Hizb Allah, Palestinian Islamic Jihad, and of not doing enough to prevent infiltration of Arab fighters into Iraq. Damascus denies the allegations.
Otari said ties between Damascus and Baghdad were "excellent" and that there would be "an Iraqi ambassador in Syria very soon."
Syria broke formal relations with Baghdad in 1982 after accusing Iraq of inciting riots by the banned Muslim Brotherhood in Syria.