Jakarta. Rupiah weakened against the US dollar on Monday as renewed military clashes between the United States and Iran fueled risk aversion and heightened concerns over global energy supplies.

Indonesian currency closed down 27 points at Rp 17,948 per US dollar, compared with Rp 17,921 at the previous close.

Ibrahim Assuaibi, director of Traze Andalan Futures and a currency analyst, said the rupiah came under pressure after the US and Iran launched fresh attacks over the weekend.

The latest escalation followed Iran's attack on a US military base in Jordan, which killed at least two American soldiers and injured several others.

The renewed conflict has intensified concerns over the security of global energy shipping routes through the Strait of Hormuz, keeping markets on edge over potential oil supply disruptions and prompting investors to price in a higher geopolitical risk premium.

"Recent US inflation and labor market data point to a softer economic backdrop. However, investors remain focused on whether rising energy costs could complicate the Federal Reserve's efforts to bring inflation under control," Ibrahim said in a statement received on Monday.

Domestically, Ibrahim said the rupiah also faced pressure despite continued foreign capital inflows, as weaker domestic investment and sluggish household consumption are expected to keep Indonesia's economic growth below the 5% mark.

Indonesia's economy is projected to expand by around 4.9% year-on-year in the second quarter of 2026.

According to Bloomberg data as of 3:59 p.m. Jakarta time, the Singapore dollar traded at Rp 13,903, the Japanese yen at Rp 110.54, the Australian dollar at Rp 12,563, and the euro at Rp 20,527.